28655440 has 40 divisors (see below), whose sum is σ = 72682848. Its totient is φ = 10419840.

The previous prime is 28655437. The next prime is 28655441. The reversal of 28655440 is 4455682.

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

It is a super-2 number, since 2×28655440² = 1642268483187200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 28655396 and 28655405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28655441) 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, 15402 + ... + 17161.

Almost surely, 2^28655440 is an apocalyptic number.

28655440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28655440 is an abundant number, since it is smaller than the sum of its proper divisors (44027408).

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

28655440 is a wasteful number, since it uses less digits than its factorization.

28655440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32587 (or 32581 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 34.

The square root of 28655440 is about 5353.0776194634. The cubic root of 28655440 is about 306.0100527832.

The spelling of 28655440 in words is "twenty-eight million, six hundred fifty-five thousand, four hundred forty".