21918597120 has 720 divisors, whose sum is σ = 90292220928. Its totient is φ = 4812963840.

The previous prime is 21918597119. The next prime is 21918597121. The reversal of 21918597120 is 2179581912.

21918597120 is a `hidden beast` number, since 21 + 9 + 18 + 597 + 1 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (21918597119) and next prime (21918597121).

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21918597121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 159989692 + ... + 159989828.

Almost surely, 2^21918597120 is an apocalyptic number.

21918597120 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 21918597120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45146110464).

21918597120 is an abundant number, since it is smaller than the sum of its proper divisors (68373623808).

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

21918597120 is a wasteful number, since it uses less digits than its factorization.

21918597120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 45.

The spelling of 21918597120 in words is "twenty-one billion, nine hundred eighteen million, five hundred ninety-seven thousand, one hundred twenty".