977128421 has 2 divisors, whose sum is σ = 977128422. Its totient is φ = 977128420.

The previous prime is 977128391. The next prime is 977128423. The reversal of 977128421 is 124821779.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 843263521 + 133864900 = 29039^2 + 11570^2 .

It is a cyclic number.

It is not a de Polignac number, because 977128421 - 2¹⁸ = 976866277 is a prime.

It is a super-2 number, since 2×977128421² = 1909559902251906482, which contains 22 as substring.

Together with 977128423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (977128423) 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, 488564210 + 488564211.

It is an arithmetic number, because the mean of its divisors is an integer number (488564211).

Almost surely, 2^977128421 is an apocalyptic number.

It is an amenable number.

977128421 is a deficient number, since it is larger than the sum of its proper divisors (1).

977128421 is an equidigital number, since it uses as much as digits as its factorization.

977128421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 41.

The square root of 977128421 is about 31259.0534245681. The cubic root of 977128421 is about 992.3172671048.

The spelling of 977128421 in words is "nine hundred seventy-seven million, one hundred twenty-eight thousand, four hundred twenty-one".