21021402613251 has 16 divisors (see below), whose sum is σ = 28073795297184. Its totient is φ = 13991656353024.

The previous prime is 21021402613247. The next prime is 21021402613259. The reversal of 21021402613251 is 15231620412012.

It is not a de Polignac number, because 21021402613251 - 2² = 21021402613247 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21021402613259) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2749591 + ... + 7042943.

It is an arithmetic number, because the mean of its divisors is an integer number (1754612206074).

Almost surely, 2^{21021402613251} is an apocalyptic number.

21021402613251 is a deficient number, since it is larger than the sum of its proper divisors (7052392683933).

21021402613251 is a wasteful number, since it uses less digits than its factorization.

21021402613251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4295990.

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21021402613251 in words is "twenty-one trillion, twenty-one billion, four hundred two million, six hundred thirteen thousand, two hundred fifty-one".