28631720 has 32 divisors (see below), whose sum is σ = 69378120. Its totient is φ = 10571520.

The previous prime is 28631719. The next prime is 28631731. The reversal of 28631720 is 2713682.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17355556 + 11276164 = 4166^2 + 3358^2 .

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, 27011 + ... + 28050.

Almost surely, 2^28631720 is an apocalyptic number.

28631720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28631720 is an abundant number, since it is smaller than the sum of its proper divisors (40746400).

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

28631720 is a wasteful number, since it uses less digits than its factorization.

28631720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55085 (or 55081 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 28631720 is about 5350.8616128620. The cubic root of 28631720 is about 305.9255945655.

The spelling of 28631720 in words is "twenty-eight million, six hundred thirty-one thousand, seven hundred twenty".