28131664 has 20 divisors (see below), whose sum is σ = 59460480. Its totient is φ = 12787040.

The previous prime is 28131661. The next prime is 28131671. The reversal of 28131664 is 46613182.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28131661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79744 + ... + 80095.

It is an arithmetic number, because the mean of its divisors is an integer number (2973024).

Almost surely, 2^28131664 is an apocalyptic number.

It is an amenable number.

28131664 is an abundant number, since it is smaller than the sum of its proper divisors (31328816).

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

28131664 is a wasteful number, since it uses less digits than its factorization.

28131664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159858 (or 159852 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 28131664 is about 5303.9291096318. The cubic root of 28131664 is about 304.1341167228.

The spelling of 28131664 in words is "twenty-eight million, one hundred thirty-one thousand, six hundred sixty-four".