21007046251 has 16 divisors (see below), whose sum is σ = 23392641024. Its totient is φ = 18762758784.

The previous prime is 21007046213. The next prime is 21007046279. The reversal of 21007046251 is 15264070012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21007046251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21007040251) 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 in 15 ways as a sum of consecutive naturals, for example, 161865 + ... + 261178.

It is an arithmetic number, because the mean of its divisors is an integer number (1462040064).

Almost surely, 2^21007046251 is an apocalyptic number.

21007046251 is a deficient number, since it is larger than the sum of its proper divisors (2385594773).

21007046251 is a wasteful number, since it uses less digits than its factorization.

21007046251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423210.

The product of its (nonzero) digits is 3360, while the sum is 28.

The spelling of 21007046251 in words is "twenty-one billion, seven million, forty-six thousand, two hundred fifty-one".