21630975251 has 2 divisors, whose sum is σ = 21630975252. Its totient is φ = 21630975250.

The previous prime is 21630975221. The next prime is 21630975293. The reversal of 21630975251 is 15257903612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21630975251 - 2³⁰ = 20557233427 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21630975199 and 21630975208.

It is not a weakly prime, because it can be changed into another prime (21630975221) 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, 10815487625 + 10815487626.

It is an arithmetic number, because the mean of its divisors is an integer number (10815487626).

Almost surely, 2^21630975251 is an apocalyptic number.

21630975251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21630975251 is an equidigital number, since it uses as much as digits as its factorization.

21630975251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 41.

The spelling of 21630975251 in words is "twenty-one billion, six hundred thirty million, nine hundred seventy-five thousand, two hundred fifty-one".