21082431 has 16 divisors (see below), whose sum is σ = 29964384. Its totient is φ = 13138944.

The previous prime is 21082423. The next prime is 21082447. The reversal of 21082431 is 13428012.

It is not a de Polignac number, because 21082431 - 2³ = 21082423 is a prime.

It is a super-2 number, since 2×21082431² = 888937793739522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21082398 and 21082407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21082331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6691 + ... + 9323.

It is an arithmetic number, because the mean of its divisors is an integer number (1872774).

Almost surely, 2^21082431 is an apocalyptic number.

21082431 is a deficient number, since it is larger than the sum of its proper divisors (8881953).

21082431 is a wasteful number, since it uses less digits than its factorization.

21082431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2810.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21082431 is about 4591.5608457256. The cubic root of 21082431 is about 276.2529318635.

The spelling of 21082431 in words is "twenty-one million, eighty-two thousand, four hundred thirty-one".