21251345670 has 48 divisors (see below), whose sum is σ = 55442146032. Its totient is φ = 5647677120.

The previous prime is 21251345659. The next prime is 21251345683. The reversal of 21251345670 is 7654315212.

21251345670 is a `hidden beast` number, since 2 + 1 + 251 + 345 + 67 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 376576 + ... + 429315.

It is an arithmetic number, because the mean of its divisors is an integer number (1155044709).

Almost surely, 2^21251345670 is an apocalyptic number.

21251345670 is an abundant number, since it is smaller than the sum of its proper divisors (34190800362).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21251345670 is a wasteful number, since it uses less digits than its factorization.

21251345670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806197 (or 806194 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 21251345670 in words is "twenty-one billion, two hundred fifty-one million, three hundred forty-five thousand, six hundred seventy".