87191020 has 24 divisors (see below), whose sum is σ = 209258784. Its totient is φ = 29894016.

The previous prime is 87190997. The next prime is 87191033. The reversal of 87191020 is 2019178.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 87191020.

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, 311257 + ... + 311536.

It is an arithmetic number, because the mean of its divisors is an integer number (8719116).

Almost surely, 2^87191020 is an apocalyptic number.

It is an amenable number.

87191020 is an abundant number, since it is smaller than the sum of its proper divisors (122067764).

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

87191020 is a wasteful number, since it uses less digits than its factorization.

87191020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622809 (or 622807 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 87191020 is about 9337.6131853917. The cubic root of 87191020 is about 443.4288234707.

The spelling of 87191020 in words is "eighty-seven million, one hundred ninety-one thousand, twenty".