31121977 has 2 divisors, whose sum is σ = 31121978. Its totient is φ = 31121976.

The previous prime is 31121963. The next prime is 31121983. The reversal of 31121977 is 77912113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28987456 + 2134521 = 5384^2 + 1461^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121977 - 2¹⁹ = 30597689 is a prime.

It is not a weakly prime, because it can be changed into another prime (31121957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560988 + 15560989.

It is an arithmetic number, because the mean of its divisors is an integer number (15560989).

Almost surely, 2^31121977 is an apocalyptic number.

It is an amenable number.

31121977 is a deficient number, since it is larger than the sum of its proper divisors (1).

31121977 is an equidigital number, since it uses as much as digits as its factorization.

31121977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2646, while the sum is 31.

The square root of 31121977 is about 5578.7074667883. The cubic root of 31121977 is about 314.5495434296.

The spelling of 31121977 in words is "thirty-one million, one hundred twenty-one thousand, nine hundred seventy-seven".