977731021 has 2 divisors, whose sum is σ = 977731022. Its totient is φ = 977731020.

The previous prime is 977730967. The next prime is 977731037. The reversal of 977731021 is 120137779.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 810028521 + 167702500 = 28461^2 + 12950^2 .

It is a cyclic number.

It is not a de Polignac number, because 977731021 - 2⁷ = 977730893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (977731061) by changing a digit.

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 as a sum of consecutive naturals, namely, 488865510 + 488865511.

It is an arithmetic number, because the mean of its divisors is an integer number (488865511).

Almost surely, 2^977731021 is an apocalyptic number.

It is an amenable number.

977731021 is a deficient number, since it is larger than the sum of its proper divisors (1).

977731021 is an equidigital number, since it uses as much as digits as its factorization.

977731021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18522, while the sum is 37.

The square root of 977731021 is about 31268.6907464959. The cubic root of 977731021 is about 992.5212141980.

The spelling of 977731021 in words is "nine hundred seventy-seven million, seven hundred thirty-one thousand, twenty-one".