28511531 has 2 divisors, whose sum is σ = 28511532. Its totient is φ = 28511530.

The previous prime is 28511521. The next prime is 28511551. The reversal of 28511531 is 13511582.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28511531 - 2¹⁴ = 28495147 is a prime.

It is a super-2 number, since 2×28511531² = 1625814799927922, 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 28511531.

It is not a weakly prime, because it can be changed into another prime (28511521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14255765 + 14255766.

It is an arithmetic number, because the mean of its divisors is an integer number (14255766).

Almost surely, 2^28511531 is an apocalyptic number.

28511531 is a deficient number, since it is larger than the sum of its proper divisors (1).

28511531 is an equidigital number, since it uses as much as digits as its factorization.

28511531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1200, while the sum is 26.

The square root of 28511531 is about 5339.6189938983. The cubic root of 28511531 is about 305.4969270997.

The spelling of 28511531 in words is "twenty-eight million, five hundred eleven thousand, five hundred thirty-one".