21511316644 has 24 divisors (see below), whose sum is σ = 38022659136. Its totient is φ = 10648092000.

The previous prime is 21511316627. The next prime is 21511316657. The reversal of 21511316644 is 44661311512.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171849 + ... + 269359.

It is an arithmetic number, because the mean of its divisors is an integer number (1584277464).

Almost surely, 2^21511316644 is an apocalyptic number.

It is an amenable number.

21511316644 is a deficient number, since it is larger than the sum of its proper divisors (16511342492).

21511316644 is a wasteful number, since it uses less digits than its factorization.

21511316644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98067 (or 98065 counting only the distinct ones).

The product of its digits is 17280, while the sum is 34.

The spelling of 21511316644 in words is "twenty-one billion, five hundred eleven million, three hundred sixteen thousand, six hundred forty-four".