21290179220 has 24 divisors (see below), whose sum is σ = 44745225000. Its totient is φ = 8509243392.

The previous prime is 21290179111. The next prime is 21290179247. The reversal of 21290179220 is 2297109212.

It can be written as a sum of positive squares in 4 ways, for example, as 1212989584 + 20077189636 = 34828^2 + 141694^2 .

It is a congruent number.

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, 401165 + ... + 451124.

It is an arithmetic number, because the mean of its divisors is an integer number (1864384375).

Almost surely, 2^21290179220 is an apocalyptic number.

21290179220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21290179220 is an abundant number, since it is smaller than the sum of its proper divisors (23455045780).

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

21290179220 is a wasteful number, since it uses less digits than its factorization.

21290179220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853547 (or 853545 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 35.

The spelling of 21290179220 in words is "twenty-one billion, two hundred ninety million, one hundred seventy-nine thousand, two hundred twenty".