21597229740 has 96 divisors (see below), whose sum is σ = 62807996160. Its totient is φ = 5538400000.

The previous prime is 21597229739. The next prime is 21597229817. The reversal of 21597229740 is 4792279512.

It is a self number, because there is not a number n which added to its sum of digits gives 21597229740.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 412015 + ... + 461465.

It is an arithmetic number, because the mean of its divisors is an integer number (654249960).

Almost surely, 2^21597229740 is an apocalyptic number.

21597229740 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 21597229740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31403998080).

21597229740 is an abundant number, since it is smaller than the sum of its proper divisors (41210766420).

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

21597229740 is a wasteful number, since it uses less digits than its factorization.

21597229740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49743 (or 49741 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 48.

The spelling of 21597229740 in words is "twenty-one billion, five hundred ninety-seven million, two hundred twenty-nine thousand, seven hundred forty".