28731931 has 2 divisors, whose sum is σ = 28731932. Its totient is φ = 28731930.

The previous prime is 28731919. The next prime is 28731949. The reversal of 28731931 is 13913782.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28731931 - 2⁷ = 28731803 is a prime.

It is a super-2 number, since 2×28731931² = 1651047717977522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28731631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14365965 + 14365966.

It is an arithmetic number, because the mean of its divisors is an integer number (14365966).

Almost surely, 2^28731931 is an apocalyptic number.

28731931 is a deficient number, since it is larger than the sum of its proper divisors (1).

28731931 is an equidigital number, since it uses as much as digits as its factorization.

28731931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 34.

The square root of 28731931 is about 5360.2174396194. The cubic root of 28731931 is about 306.2820920972.

The spelling of 28731931 in words is "twenty-eight million, seven hundred thirty-one thousand, nine hundred thirty-one".