21990166580 has 12 divisors (see below), whose sum is σ = 46179349860. Its totient is φ = 8796066624.

The previous prime is 21990166537. The next prime is 21990166619. The reversal of 21990166580 is 8566109912.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4332009124 + 17658157456 = 65818^2 + 132884^2 .

It is a super-2 number, since 2×21990166580² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549754145 + ... + 549754184.

It is an arithmetic number, because the mean of its divisors is an integer number (3848279155).

Almost surely, 2^21990166580 is an apocalyptic number.

21990166580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21990166580 is an abundant number, since it is smaller than the sum of its proper divisors (24189183280).

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

21990166580 is a wasteful number, since it uses less digits than its factorization.

21990166580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1099508338 (or 1099508336 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 47.

The spelling of 21990166580 in words is "twenty-one billion, nine hundred ninety million, one hundred sixty-six thousand, five hundred eighty".