20181407 has 4 divisors (see below), whose sum is σ = 20190696. Its totient is φ = 20172120.

The previous prime is 20181353. The next prime is 20181437. The reversal of 20181407 is 70418102.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 70418102 = 2 ⋅35209051.

It is a cyclic number.

It is not a de Polignac number, because 20181407 - 2⁸ = 20181151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20181437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 557 + ... + 6377.

It is an arithmetic number, because the mean of its divisors is an integer number (5047674).

Almost surely, 2^20181407 is an apocalyptic number.

20181407 is a deficient number, since it is larger than the sum of its proper divisors (9289).

20181407 is an equidigital number, since it uses as much as digits as its factorization.

20181407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9288.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 20181407 is about 4492.3720905553. The cubic root of 20181407 is about 272.2599833653.

Adding to 20181407 its reverse (70418102), we get a palindrome (90599509).

The spelling of 20181407 in words is "twenty million, one hundred eighty-one thousand, four hundred seven".