21386722564 has 9 divisors (see below), whose sum is σ = 37427276341. Its totient is φ = 10693215040.

The previous prime is 21386722559. The next prime is 21386722589. The reversal of 21386722564 is 46522768312.

The square root of 21386722564 is 146242.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1494440964 + 19892281600 = 38658^2 + 141040^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 255924 + ... + 329044.

Almost surely, 2^21386722564 is an apocalyptic number.

21386722564 is the 146242-nd square number.

It is an amenable number.

21386722564 is a deficient number, since it is larger than the sum of its proper divisors (16040553777).

21386722564 is an frugal number, since it uses more digits than its factorization.

21386722564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146246 (or 73123 counting only the distinct ones).

The product of its digits is 967680, while the sum is 46.

The spelling of 21386722564 in words is "twenty-one billion, three hundred eighty-six million, seven hundred twenty-two thousand, five hundred sixty-four".