31281999977 has 2 divisors, whose sum is σ = 31281999978. Its totient is φ = 31281999976.

The previous prime is 31281999967. The next prime is 31281999997. The reversal of 31281999977 is 77999918213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25430361961 + 5851638016 = 159469^2 + 76496^2 .

It is a cyclic number.

It is not a de Polignac number, because 31281999977 - 2¹⁶ = 31281934441 is a prime.

It is a super-2 number, since 2×31281999977² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31281999967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15640999988 + 15640999989.

It is an arithmetic number, because the mean of its divisors is an integer number (15640999989).

Almost surely, 2^31281999977 is an apocalyptic number.

It is an amenable number.

31281999977 is a deficient number, since it is larger than the sum of its proper divisors (1).

31281999977 is an equidigital number, since it uses as much as digits as its factorization.

31281999977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15431472, while the sum is 65.

The spelling of 31281999977 in words is "thirty-one billion, two hundred eighty-one million, nine hundred ninety-nine thousand, nine hundred seventy-seven".