20870531 has 8 divisors (see below), whose sum is σ = 23966400. Its totient is φ = 17974440.

The previous prime is 20870513. The next prime is 20870573. The reversal of 20870531 is 13507802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20870531 - 2⁶ = 20870467 is a prime.

It is a super-2 number, since 2×20870531² = 871158128443922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20870531.

It is not an unprimeable number, because it can be changed into a prime (20870501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49721 + ... + 50138.

It is an arithmetic number, because the mean of its divisors is an integer number (2995800).

Almost surely, 2^20870531 is an apocalyptic number.

20870531 is a deficient number, since it is larger than the sum of its proper divisors (3095869).

20870531 is a wasteful number, since it uses less digits than its factorization.

20870531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99889.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 20870531 is about 4568.4276288456. The cubic root of 20870531 is about 275.3242720230.

The spelling of 20870531 in words is "twenty million, eight hundred seventy thousand, five hundred thirty-one".