21918154752 has 192 divisors, whose sum is σ = 68200701660. Its totient is φ = 6742867968.

The previous prime is 21918154751. The next prime is 21918154807. The reversal of 21918154752 is 25745181912.

21918154752 is a `hidden beast` number, since 21 + 9 + 1 + 81 + 547 + 5 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21404860416 + 513294336 = 146304^2 + 22656^2 .

It is a tau number, because it is divible by the number of its divisors (192).

It is a junction number, because it is equal to n+sod(n) for n = 21918154698 and 21918154707.

It is not an unprimeable number, because it can be changed into a prime (21918154751) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3830998 + ... + 3836714.

Almost surely, 2^21918154752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21918154752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34100350830).

21918154752 is an abundant number, since it is smaller than the sum of its proper divisors (46282546908).

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

21918154752 is an equidigital number, since it uses as much as digits as its factorization.

21918154752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5766 (or 5735 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The spelling of 21918154752 in words is "twenty-one billion, nine hundred eighteen million, one hundred fifty-four thousand, seven hundred fifty-two".