21945773980 has 48 divisors (see below), whose sum is σ = 50841753984. Its totient is φ = 7905415680.

The previous prime is 21945773963. The next prime is 21945773987. The reversal of 21945773980 is 8937754912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945773987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1018692 + ... + 1040011.

It is an arithmetic number, because the mean of its divisors is an integer number (1059203208).

Almost surely, 2^21945773980 is an apocalyptic number.

21945773980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21945773980 is an abundant number, since it is smaller than the sum of its proper divisors (28895980004).

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

21945773980 is a wasteful number, since it uses less digits than its factorization.

21945773980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2058766 (or 2058764 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 55.

The spelling of 21945773980 in words is "twenty-one billion, nine hundred forty-five million, seven hundred seventy-three thousand, nine hundred eighty".