21981080940 has 96 divisors (see below), whose sum is σ = 75750205440. Its totient is φ = 4637765376.

The previous prime is 21981080939. The next prime is 21981080951. The reversal of 21981080940 is 4908018912.

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

It is a junction number, because it is equal to n+sod(n) for n = 21981080892 and 21981080901.

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, 2007460 + ... + 2018379.

It is an arithmetic number, because the mean of its divisors is an integer number (789064640).

Almost surely, 2^21981080940 is an apocalyptic number.

21981080940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21981080940 is an abundant number, since it is smaller than the sum of its proper divisors (53769124500).

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

21981080940 is a wasteful number, since it uses less digits than its factorization.

21981080940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4025871 (or 4025869 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 42.

The spelling of 21981080940 in words is "twenty-one billion, nine hundred eighty-one million, eighty thousand, nine hundred forty".