21251051431 has 2 divisors, whose sum is σ = 21251051432. Its totient is φ = 21251051430.

The previous prime is 21251051401. The next prime is 21251051443. The reversal of 21251051431 is 13415015212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21251051431 - 2²⁵ = 21217496999 is a prime.

It is a super-2 number, since 2×21251051431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21251051396 and 21251051405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21251051401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625525715 + 10625525716.

It is an arithmetic number, because the mean of its divisors is an integer number (10625525716).

Almost surely, 2^21251051431 is an apocalyptic number.

21251051431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21251051431 is an equidigital number, since it uses as much as digits as its factorization.

21251051431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 21251051431 its reverse (13415015212), we get a palindrome (34666066643).

The spelling of 21251051431 in words is "twenty-one billion, two hundred fifty-one million, fifty-one thousand, four hundred thirty-one".