28638890 has 64 divisors (see below), whose sum is σ = 63210240. Its totient is φ = 9123840.

The previous prime is 28638889. The next prime is 28638893. The reversal of 28638890 is 9883682.

It is not an unprimeable number, because it can be changed into a prime (28638893) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80954 + ... + 81306.

It is an arithmetic number, because the mean of its divisors is an integer number (987660).

Almost surely, 2^28638890 is an apocalyptic number.

28638890 is an abundant number, since it is smaller than the sum of its proper divisors (34571350).

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

28638890 is a wasteful number, since it uses less digits than its factorization.

28638890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447.

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 28638890 is about 5351.5315564799. The cubic root of 28638890 is about 305.9511292224.

The spelling of 28638890 in words is "twenty-eight million, six hundred thirty-eight thousand, eight hundred ninety".