21253431435251 has 4 divisors (see below), whose sum is σ = 21459775429872. Its totient is φ = 21047087440632.

The previous prime is 21253431435217. The next prime is 21253431435259. The reversal of 21253431435251 is 15253413435212.

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

It is a cyclic number.

It is not a de Polignac number, because 21253431435251 - 2²⁶ = 21253364326387 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21253431435199 and 21253431435208.

It is not an unprimeable number, because it can be changed into a prime (21253431435259) 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, 103171997156 + ... + 103171997361.

It is an arithmetic number, because the mean of its divisors is an integer number (5364943857468).

Almost surely, 2^{21253431435251} is an apocalyptic number.

21253431435251 is a deficient number, since it is larger than the sum of its proper divisors (206343994621).

21253431435251 is a wasteful number, since it uses less digits than its factorization.

21253431435251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206343994620.

The product of its digits is 432000, while the sum is 41.

The spelling of 21253431435251 in words is "twenty-one trillion, two hundred fifty-three billion, four hundred thirty-one million, four hundred thirty-five thousand, two hundred fifty-one".