21097776404 has 6 divisors (see below), whose sum is σ = 36921108714. Its totient is φ = 10548888200.

The previous prime is 21097776389. The next prime is 21097776461. The reversal of 21097776404 is 40467779012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16770768004 + 4327008400 = 129502^2 + 65780^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2637222047 + ... + 2637222054.

It is an arithmetic number, because the mean of its divisors is an integer number (6153518119).

Almost surely, 2^21097776404 is an apocalyptic number.

It is an amenable number.

21097776404 is a deficient number, since it is larger than the sum of its proper divisors (15823332310).

21097776404 is a wasteful number, since it uses less digits than its factorization.

21097776404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5274444105 (or 5274444103 counting only the distinct ones).

The product of its (nonzero) digits is 592704, while the sum is 47.

The spelling of 21097776404 in words is "twenty-one billion, ninety-seven million, seven hundred seventy-six thousand, four hundred four".