21171086790 has 64 divisors (see below), whose sum is σ = 58936011264. Its totient is φ = 4766876928.

The previous prime is 21171086789. The next prime is 21171086831. The reversal of 21171086790 is 9768017112.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 738279 + ... + 766418.

It is an arithmetic number, because the mean of its divisors is an integer number (920875176).

Almost surely, 2^21171086790 is an apocalyptic number.

21171086790 is an abundant number, since it is smaller than the sum of its proper divisors (37764924474).

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

21171086790 is a wasteful number, since it uses less digits than its factorization.

21171086790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1504781.

The product of its (nonzero) digits is 42336, while the sum is 42.

The spelling of 21171086790 in words is "twenty-one billion, one hundred seventy-one million, eighty-six thousand, seven hundred ninety".