21172839174144 has 546 divisors, whose sum is σ = 73846597022610. Its totient is φ = 6049340817408.

The previous prime is 21172839174061. The next prime is 21172839174161. The reversal of 21172839174144 is 44147193827112.

21172839174144 is a `hidden beast` number, since 2 + 1 + 172 + 8 + 391 + 7 + 41 + 44 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13432870047744 + 7739969126400 = 3665088^2 + 2782080^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 146240862 + ... + 146385570.

Almost surely, 2^{21172839174144} is an apocalyptic number.

21172839174144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21172839174144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36923298511305).

21172839174144 is an abundant number, since it is smaller than the sum of its proper divisors (52673757848466).

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

21172839174144 is an frugal number, since it uses more digits than its factorization.

21172839174144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144765 (or 144721 counting only the distinct ones).

The product of its digits is 2709504, while the sum is 54.

The spelling of 21172839174144 in words is "twenty-one trillion, one hundred seventy-two billion, eight hundred thirty-nine million, one hundred seventy-four thousand, one hundred forty-four".