21025555631 has 2 divisors, whose sum is σ = 21025555632. Its totient is φ = 21025555630.

The previous prime is 21025555619. The next prime is 21025555637. The reversal of 21025555631 is 13655552012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21025555631 is a prime.

It is a super-2 number, since 2×21025555631² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21025555591 and 21025555600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21025555637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10512777815 + 10512777816.

It is an arithmetic number, because the mean of its divisors is an integer number (10512777816).

Almost surely, 2^21025555631 is an apocalyptic number.

21025555631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21025555631 is an equidigital number, since it uses as much as digits as its factorization.

21025555631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45000, while the sum is 35.

The spelling of 21025555631 in words is "twenty-one billion, twenty-five million, five hundred fifty-five thousand, six hundred thirty-one".