28939690 has 16 divisors (see below), whose sum is σ = 56098728. Its totient is φ = 10685376.

The previous prime is 28939637. The next prime is 28939697. The reversal of 28939690 is 9693982.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13549761 + 15389929 = 3681^2 + 3923^2 .

It is a super-2 number, since 2×28939690² = 1675011314592200, 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 28939690.

It is not an unprimeable number, because it can be changed into a prime (28939697) 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, 111177 + ... + 111436.

Almost surely, 2^28939690 is an apocalyptic number.

28939690 is a deficient number, since it is larger than the sum of its proper divisors (27159038).

28939690 is a wasteful number, since it uses less digits than its factorization.

28939690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222633.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 28939690 is about 5379.5622498490. The cubic root of 28939690 is about 307.0185561045.

The spelling of 28939690 in words is "twenty-eight million, nine hundred thirty-nine thousand, six hundred ninety".