21371730365640 has 256 divisors, whose sum is σ = 65271221452800. Its totient is φ = 5597038899200.

The previous prime is 21371730365627. The next prime is 21371730365653. The reversal of 21371730365640 is 4656303717312.

It is an interprime number because it is at equal distance from previous prime (21371730365627) and next prime (21371730365653).

It is a self number, because there is not a number n which added to its sum of digits gives 21371730365640.

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, 2420076025 + ... + 2420084855.

It is an arithmetic number, because the mean of its divisors is an integer number (254965708800).

Almost surely, 2^{21371730365640} is an apocalyptic number.

21371730365640 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 21371730365640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32635610726400).

21371730365640 is an abundant number, since it is smaller than the sum of its proper divisors (43899491087160).

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

21371730365640 is a wasteful number, since it uses less digits than its factorization.

21371730365640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9988 (or 9984 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 48.

The spelling of 21371730365640 in words is "twenty-one trillion, three hundred seventy-one billion, seven hundred thirty million, three hundred sixty-five thousand, six hundred forty".