21621881148 has 96 divisors (see below), whose sum is σ = 59479193088. Its totient is φ = 5985619200.

The previous prime is 21621881119. The next prime is 21621881207. The reversal of 21621881148 is 84118812612.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

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, 311818 + ... + 374798.

It is an arithmetic number, because the mean of its divisors is an integer number (619574928).

Almost surely, 2^21621881148 is an apocalyptic number.

21621881148 is a gapful number since it is divisible by the number (28) 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 21621881148, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29739596544).

21621881148 is an abundant number, since it is smaller than the sum of its proper divisors (37857311940).

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

21621881148 is a wasteful number, since it uses less digits than its factorization.

21621881148 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63123 (or 63121 counting only the distinct ones).

The product of its digits is 49152, while the sum is 42.

The spelling of 21621881148 in words is "twenty-one billion, six hundred twenty-one million, eight hundred eighty-one thousand, one hundred forty-eight".