21455993040 has 40 divisors (see below), whose sum is σ = 66513579168. Its totient is φ = 5721598080.

The previous prime is 21455992981. The next prime is 21455993047. The reversal of 21455993040 is 4039955412.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 21455992983 and 21455993001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21455993047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44699746 + ... + 44700225.

Almost surely, 2^21455993040 is an apocalyptic number.

21455993040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21455993040 is an abundant number, since it is smaller than the sum of its proper divisors (45057586128).

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

21455993040 is a wasteful number, since it uses less digits than its factorization.

21455993040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89399987 (or 89399981 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 42.

The spelling of 21455993040 in words is "twenty-one billion, four hundred fifty-five million, nine hundred ninety-three thousand, forty".