28690640 has 40 divisors (see below), whose sum is σ = 72772128. Its totient is φ = 10432640.

The previous prime is 28690639. The next prime is 28690661. The reversal of 28690640 is 4609682.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 28690640.

It is a congruent number.

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, 15422 + ... + 17181.

Almost surely, 2^28690640 is an apocalyptic number.

28690640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28690640 is an abundant number, since it is smaller than the sum of its proper divisors (44081488).

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

28690640 is a wasteful number, since it uses less digits than its factorization.

28690640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32627 (or 32621 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 28690640 is about 5356.3644386841. The cubic root of 28690640 is about 306.1353012098.

The spelling of 28690640 in words is "twenty-eight million, six hundred ninety thousand, six hundred forty".