21800016251 has 12 divisors (see below), whose sum is σ = 24108197472. Its totient is φ = 19694933856.

The previous prime is 21800016247. The next prime is 21800016281. The reversal of 21800016251 is 15261000812.

It is not a de Polignac number, because 21800016251 - 2² = 21800016247 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21800016251.

It is not an unprimeable number, because it can be changed into a prime (21800016281) 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 in 11 ways as a sum of consecutive naturals, for example, 1364336 + ... + 1380221.

It is an arithmetic number, because the mean of its divisors is an integer number (2009016456).

Almost surely, 2^21800016251 is an apocalyptic number.

21800016251 is a deficient number, since it is larger than the sum of its proper divisors (2308181221).

21800016251 is a wasteful number, since it uses less digits than its factorization.

21800016251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2744630 (or 2744617 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 26.

The spelling of 21800016251 in words is "twenty-one billion, eight hundred million, sixteen thousand, two hundred fifty-one".