21651421022464 has 36 divisors (see below), whose sum is σ = 43261877451520. Its totient is φ = 10814786357760.

The previous prime is 21651421022381. The next prime is 21651421022489. The reversal of 21651421022464 is 46422012415612.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42418284 + ... + 42925675.

Almost surely, 2^{21651421022464} is an apocalyptic number.

It is an amenable number.

21651421022464 is a deficient number, since it is larger than the sum of its proper divisors (21610456429056).

21651421022464 is an frugal number, since it uses more digits than its factorization.

21651421022464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85344966 (or 85344952 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 40.

The spelling of 21651421022464 in words is "twenty-one trillion, six hundred fifty-one billion, four hundred twenty-one million, twenty-two thousand, four hundred sixty-four".