20155013 has 4 divisors (see below), whose sum is σ = 21340620. Its totient is φ = 18969408.

The previous prime is 20154961. The next prime is 20155021. The reversal of 20155013 is 31055102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10125124 + 10029889 = 3182^2 + 3167^2 .

It is a cyclic number.

It is not a de Polignac number, because 20155013 - 2¹⁶ = 20089477 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1185589 = 20155013 / (2 + 0 + 1 + 5 + 5 + 0 + 1 + 3).

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20154982 and 20155000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20155073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 592778 + ... + 592811.

It is an arithmetic number, because the mean of its divisors is an integer number (5335155).

Almost surely, 2^20155013 is an apocalyptic number.

It is an amenable number.

20155013 is a deficient number, since it is larger than the sum of its proper divisors (1185607).

20155013 is a wasteful number, since it uses less digits than its factorization.

20155013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185606.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 20155013 is about 4489.4334831914. The cubic root of 20155013 is about 272.1412409836.

It can be divided in two parts, 2015501 and 3, that multiplied together give a triangular number (6046503 = T₃₄₇₇).

The spelling of 20155013 in words is "twenty million, one hundred fifty-five thousand, thirteen".