21173857384240 has 320 divisors, whose sum is σ = 56382234734592. Its totient is φ = 7327776153600.

The previous prime is 21173857384213. The next prime is 21173857384249. The reversal of 21173857384240 is 4248375837112.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is not an unprimeable number, because it can be changed into a prime (21173857384249) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 214319494 + ... + 214418266.

Almost surely, 2^{21173857384240} is an apocalyptic number.

21173857384240 is a gapful number since it is divisible by the number (20) 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 21173857384240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28191117367296).

21173857384240 is an abundant number, since it is smaller than the sum of its proper divisors (35208377350352).

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

21173857384240 is a wasteful number, since it uses less digits than its factorization.

21173857384240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98988 (or 98982 counting only the distinct ones).

The product of its (nonzero) digits is 9031680, while the sum is 55.

The spelling of 21173857384240 in words is "twenty-one trillion, one hundred seventy-three billion, eight hundred fifty-seven million, three hundred eighty-four thousand, two hundred forty".