28919731 has 2 divisors, whose sum is σ = 28919732. Its totient is φ = 28919730.

The previous prime is 28919713. The next prime is 28919747. The reversal of 28919731 is 13791982.

Together with previous prime (28919713) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28919731 - 2⁷ = 28919603 is a prime.

It is a super-2 number, since 2×28919731² = 1672701682224722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28919701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14459865 + 14459866.

It is an arithmetic number, because the mean of its divisors is an integer number (14459866).

Almost surely, 2^28919731 is an apocalyptic number.

28919731 is a deficient number, since it is larger than the sum of its proper divisors (1).

28919731 is an equidigital number, since it uses as much as digits as its factorization.

28919731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 40.

The square root of 28919731 is about 5377.7068532972. The cubic root of 28919731 is about 306.9479587964.

The spelling of 28919731 in words is "twenty-eight million, nine hundred nineteen thousand, seven hundred thirty-one".