21062431 has 16 divisors (see below), whose sum is σ = 24040800. Its totient is φ = 18292608.

The previous prime is 21062429. The next prime is 21062441. The reversal of 21062431 is 13426012.

It is a cyclic number.

It is not a de Polignac number, because 21062431 - 2¹ = 21062429 is a prime.

It is a super-2 number, since 2×21062431² = 887251999259522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21062399 and 21062408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21062401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66285 + ... + 66601.

It is an arithmetic number, because the mean of its divisors is an integer number (1502550).

Almost surely, 2^21062431 is an apocalyptic number.

21062431 is a deficient number, since it is larger than the sum of its proper divisors (2978369).

21062431 is a wasteful number, since it uses less digits than its factorization.

21062431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21062431 is about 4589.3824203263. The cubic root of 21062431 is about 276.1655477807.

Adding to 21062431 its reverse (13426012), we get a palindrome (34488443).

The spelling of 21062431 in words is "twenty-one million, sixty-two thousand, four hundred thirty-one".