21177816676 has 9 divisors (see below), whose sum is σ = 37061688531. Its totient is φ = 10588762812.

The previous prime is 21177816629. The next prime is 21177816683. The reversal of 21177816676 is 67661877112.

It is a happy number.

The square root of 21177816676 is 145526.

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

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 254671 + ... + 327433.

Almost surely, 2^21177816676 is an apocalyptic number.

21177816676 is the 145526-th square number.

It is an amenable number.

21177816676 is a deficient number, since it is larger than the sum of its proper divisors (15883871855).

21177816676 is an frugal number, since it uses more digits than its factorization.

21177816676 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145530 (or 72765 counting only the distinct ones).

The product of its digits is 1185408, while the sum is 52.

The spelling of 21177816676 in words is "twenty-one billion, one hundred seventy-seven million, eight hundred sixteen thousand, six hundred seventy-six".