21898397952 has 216 divisors, whose sum is σ = 69331874976. Its totient is φ = 6869753856.

The previous prime is 21898397951. The next prime is 21898397993. The reversal of 21898397952 is 25979389812.

It is a tau number, because it is divible by the number of its divisors (216).

It is a self number, because there is not a number n which added to its sum of digits gives 21898397952.

It is not an unprimeable number, because it can be changed into a prime (21898397951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1047183 + ... + 1067889.

Almost surely, 2^21898397952 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21898397952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34665937488).

21898397952 is an abundant number, since it is smaller than the sum of its proper divisors (47433477024).

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

21898397952 is an equidigital number, since it uses as much as digits as its factorization.

21898397952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20755 (or 20729 counting only the distinct ones).

The product of its digits is 19595520, while the sum is 63.

The spelling of 21898397952 in words is "twenty-one billion, eight hundred ninety-eight million, three hundred ninety-seven thousand, nine hundred fifty-two".