28031690 has 16 divisors (see below), whose sum is σ = 52197480. Its totient is φ = 10825920.

The previous prime is 28031629. The next prime is 28031699. The reversal of 28031690 is 9613082.

It can be written as a sum of positive squares in 4 ways, for example, as 26491609 + 1540081 = 5147^2 + 1241^2 .

It is a super-2 number, since 2×28031690² = 1571551288512200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is not an unprimeable number, because it can be changed into a prime (28031699) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48041 + ... + 48620.

Almost surely, 2^28031690 is an apocalyptic number.

28031690 is a deficient number, since it is larger than the sum of its proper divisors (24165790).

28031690 is a wasteful number, since it uses less digits than its factorization.

28031690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96697.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 28031690 is about 5294.4961988843. The cubic root of 28031690 is about 303.7734129299.

The spelling of 28031690 in words is "twenty-eight million, thirty-one thousand, six hundred ninety".