21131651251 has 2 divisors, whose sum is σ = 21131651252. Its totient is φ = 21131651250.

The previous prime is 21131651231. The next prime is 21131651267. The reversal of 21131651251 is 15215613112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21131651251 - 2⁹ = 21131650739 is a prime.

It is not a weakly prime, because it can be changed into another prime (21131651201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565825625 + 10565825626.

It is an arithmetic number, because the mean of its divisors is an integer number (10565825626).

Almost surely, 2^21131651251 is an apocalyptic number.

21131651251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131651251 is an equidigital number, since it uses as much as digits as its factorization.

21131651251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The spelling of 21131651251 in words is "twenty-one billion, one hundred thirty-one million, six hundred fifty-one thousand, two hundred fifty-one".