28212731 has 2 divisors, whose sum is σ = 28212732. Its totient is φ = 28212730.

The previous prime is 28212721. The next prime is 28212749. The reversal of 28212731 is 13721282.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28212731 - 2²² = 24018427 is a prime.

It is a super-2 number, since 2×28212731² = 1591916380956722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28212731.

It is not a weakly prime, because it can be changed into another prime (28212721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14106365 + 14106366.

It is an arithmetic number, because the mean of its divisors is an integer number (14106366).

Almost surely, 2^28212731 is an apocalyptic number.

28212731 is a deficient number, since it is larger than the sum of its proper divisors (1).

28212731 is an equidigital number, since it uses as much as digits as its factorization.

28212731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 26.

The square root of 28212731 is about 5311.5657766802. The cubic root of 28212731 is about 304.4259775869.

The spelling of 28212731 in words is "twenty-eight million, two hundred twelve thousand, seven hundred thirty-one".