31977558587321 has 2 divisors, whose sum is σ = 31977558587322. Its totient is φ = 31977558587320.

The previous prime is 31977558587297. The next prime is 31977558587323. The reversal of 31977558587321 is 12378585577913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29481044826025 + 2496513761296 = 5429645^2 + 1580036^2 .

It is an emirp because it is prime and its reverse (12378585577913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31977558587321 - 2⁴² = 27579512076217 is a prime.

Together with 31977558587323, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31977558587323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15988779293660 + 15988779293661.

It is an arithmetic number, because the mean of its divisors is an integer number (15988779293661).

Almost surely, 2^{31977558587321} is an apocalyptic number.

It is an amenable number.

31977558587321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31977558587321 is an equidigital number, since it uses as much as digits as its factorization.

31977558587321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 444528000, while the sum is 71.

The spelling of 31977558587321 in words is "thirty-one trillion, nine hundred seventy-seven billion, five hundred fifty-eight million, five hundred eighty-seven thousand, three hundred twenty-one".