28521690 has 16 divisors (see below), whose sum is σ = 68452128. Its totient is φ = 7605776.

The previous prime is 28521683. The next prime is 28521707. The reversal of 28521690 is 9612582.

It is a super-2 number, since 2×28521690² = 1626973600912200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 475332 + ... + 475391.

It is an arithmetic number, because the mean of its divisors is an integer number (4278258).

Almost surely, 2^28521690 is an apocalyptic number.

28521690 is an abundant number, since it is smaller than the sum of its proper divisors (39930438).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28521690 is a wasteful number, since it uses less digits than its factorization.

28521690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950733.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 28521690 is about 5340.5701942770. The cubic root of 28521690 is about 305.5332068625.

The spelling of 28521690 in words is "twenty-eight million, five hundred twenty-one thousand, six hundred ninety".