21272120431 has 2 divisors, whose sum is σ = 21272120432. Its totient is φ = 21272120430.

The previous prime is 21272120351. The next prime is 21272120437. The reversal of 21272120431 is 13402127212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21272120431 is a prime.

It is a super-2 number, since 2×21272120431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21272120396 and 21272120405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21272120437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636060215 + 10636060216.

It is an arithmetic number, because the mean of its divisors is an integer number (10636060216).

Almost surely, 2^21272120431 is an apocalyptic number.

21272120431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21272120431 is an equidigital number, since it uses as much as digits as its factorization.

21272120431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

Adding to 21272120431 its reverse (13402127212), we get a palindrome (34674247643).

The spelling of 21272120431 in words is "twenty-one billion, two hundred seventy-two million, one hundred twenty thousand, four hundred thirty-one".