21385222791520 has 192 divisors, whose sum is σ = 58168868083200. Its totient is φ = 7277654200320.

The previous prime is 21385222791511. The next prime is 21385222791529. The reversal of 21385222791520 is 2519722258312.

It is an interprime number because it is at equal distance from previous prime (21385222791511) and next prime (21385222791529).

It is a super-2 number, since 2×21385222791520² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385222791529) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 810923935 + ... + 810950305.

It is an arithmetic number, because the mean of its divisors is an integer number (302962854600).

Almost surely, 2^{21385222791520} is an apocalyptic number.

21385222791520 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 21385222791520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29084434041600).

21385222791520 is an abundant number, since it is smaller than the sum of its proper divisors (36783645291680).

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

21385222791520 is a wasteful number, since it uses less digits than its factorization.

21385222791520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31741 (or 31733 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 49.

The spelling of 21385222791520 in words is "twenty-one trillion, three hundred eighty-five billion, two hundred twenty-two million, seven hundred ninety-one thousand, five hundred twenty".