21036504431 has 4 divisors (see below), whose sum is σ = 21037034352. Its totient is φ = 21035974512.

The previous prime is 21036504407. The next prime is 21036504443. The reversal of 21036504431 is 13440563012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21036504431 is a prime.

It is a super-2 number, since 2×21036504431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21036504394 and 21036504403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036500431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200126 + ... + 286571.

It is an arithmetic number, because the mean of its divisors is an integer number (5259258588).

Almost surely, 2^21036504431 is an apocalyptic number.

21036504431 is a deficient number, since it is larger than the sum of its proper divisors (529921).

21036504431 is an equidigital number, since it uses as much as digits as its factorization.

21036504431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529920.

The product of its (nonzero) digits is 8640, while the sum is 29.

The spelling of 21036504431 in words is "twenty-one billion, thirty-six million, five hundred four thousand, four hundred thirty-one".