28328731 has 2 divisors, whose sum is σ = 28328732. Its totient is φ = 28328730.

The previous prime is 28328693. The next prime is 28328767. The reversal of 28328731 is 13782382.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28328731 is a prime.

It is a super-2 number, since 2×28328731² = 1605034000140722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28328771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14164365 + 14164366.

It is an arithmetic number, because the mean of its divisors is an integer number (14164366).

Almost surely, 2^28328731 is an apocalyptic number.

28328731 is a deficient number, since it is larger than the sum of its proper divisors (1).

28328731 is an equidigital number, since it uses as much as digits as its factorization.

28328731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 34.

The square root of 28328731 is about 5322.4741427272. The cubic root of 28328731 is about 304.8426349370.

The spelling of 28328731 in words is "twenty-eight million, three hundred twenty-eight thousand, seven hundred thirty-one".