21581083722240 has 640 divisors, whose sum is σ = 90435080355840. Its totient is φ = 4773692620800.

The previous prime is 21581083722239. The next prime is 21581083722269. The reversal of 21581083722240 is 4222738018512.

21581083722240 is a `hidden beast` number, since 2 + 1 + 58 + 1 + 0 + 8 + 372 + 224 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14279625 + ... + 15718455.

It is an arithmetic number, because the mean of its divisors is an integer number (141304813056).

Almost surely, 2^{21581083722240} is an apocalyptic number.

21581083722240 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 21581083722240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45217540177920).

21581083722240 is an abundant number, since it is smaller than the sum of its proper divisors (68853996633600).

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

21581083722240 is a wasteful number, since it uses less digits than its factorization.

21581083722240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1438901 (or 1438879 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 21581083722240 in words is "twenty-one trillion, five hundred eighty-one billion, eighty-three million, seven hundred twenty-two thousand, two hundred forty".