31728744979 has 2 divisors, whose sum is σ = 31728744980. Its totient is φ = 31728744978.

The previous prime is 31728744977. The next prime is 31728744991. The reversal of 31728744979 is 97944782713.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31728744979 - 2¹ = 31728744977 is a prime.

Together with 31728744977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (31728744977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15864372489 + 15864372490.

It is an arithmetic number, because the mean of its divisors is an integer number (15864372490).

Almost surely, 2^31728744979 is an apocalyptic number.

31728744979 is a deficient number, since it is larger than the sum of its proper divisors (1).

31728744979 is an equidigital number, since it uses as much as digits as its factorization.

31728744979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21337344, while the sum is 61.

The spelling of 31728744979 in words is "thirty-one billion, seven hundred twenty-eight million, seven hundred forty-four thousand, nine hundred seventy-nine".