21118995840 has 64 divisors (see below), whose sum is σ = 67316805360. Its totient is φ = 5631731712.

The previous prime is 21118995803. The next prime is 21118995847. The reversal of 21118995840 is 4859981112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21118995840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21118995847) 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, 5497819 + ... + 5501658.

Almost surely, 2^21118995840 is an apocalyptic number.

21118995840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21118995840 is an abundant number, since it is smaller than the sum of its proper divisors (46197809520).

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

21118995840 is a wasteful number, since it uses less digits than its factorization.

21118995840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10999499 (or 10999487 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 48.

The spelling of 21118995840 in words is "twenty-one billion, one hundred eighteen million, nine hundred ninety-five thousand, eight hundred forty".