21957311040 has 224 divisors, whose sum is σ = 80571075840. Its totient is φ = 4962287616.

The previous prime is 21957311039. The next prime is 21957311081. The reversal of 21957311040 is 4011375912.

It is a tau number, because it is divible by the number of its divisors (224).

It is a junction number, because it is equal to n+sod(n) for n = 21957310992 and 21957311010.

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, 579724 + ... + 616436.

Almost surely, 2^21957311040 is an apocalyptic number.

21957311040 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 21957311040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40285537920).

21957311040 is an abundant number, since it is smaller than the sum of its proper divisors (58613764800).

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

21957311040 is a wasteful number, since it uses less digits than its factorization.

21957311040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36829 (or 36819 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 33.

Adding to 21957311040 its reverse (4011375912), we get a palindrome (25968686952).

The spelling of 21957311040 in words is "twenty-one billion, nine hundred fifty-seven million, three hundred eleven thousand, forty".