21402179810020 has 24 divisors (see below), whose sum is σ = 44944668962424. Its totient is φ = 8560854521856.

The previous prime is 21402179809949. The next prime is 21402179810021. The reversal of 21402179810020 is 2001897120412.

It can be written as a sum of positive squares in 4 ways, for example, as 40479025636 + 21361700784384 = 201194^2 + 4621872^2 .

It is not an unprimeable number, because it can be changed into a prime (21402179810021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14322564 + ... + 15746116.

It is an arithmetic number, because the mean of its divisors is an integer number (1872694540101).

Almost surely, 2^{21402179810020} is an apocalyptic number.

21402179810020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21402179810020 is an abundant number, since it is smaller than the sum of its proper divisors (23542489152404).

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

21402179810020 is a wasteful number, since it uses less digits than its factorization.

21402179810020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175279 (or 2175277 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The spelling of 21402179810020 in words is "twenty-one trillion, four hundred two billion, one hundred seventy-nine million, eight hundred ten thousand, twenty".