21903545664 has 1176 divisors, whose sum is σ = 90389281248. Its totient is φ = 5173217280.

The previous prime is 21903545621. The next prime is 21903545681. The reversal of 21903545664 is 46654530912.

21903545664 is a `hidden beast` number, since 2 + 190 + 3 + 5 + 456 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (1176).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 167 ways as a sum of consecutive naturals, for example, 326918559 + ... + 326918625.

Almost surely, 2^21903545664 is an apocalyptic number.

21903545664 is a gapful number since it is divisible by the number (24) 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 21903545664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45194640624).

21903545664 is an abundant number, since it is smaller than the sum of its proper divisors (68485735584).

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

21903545664 is a wasteful number, since it uses less digits than its factorization.

21903545664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 21903545664 in words is "twenty-one billion, nine hundred three million, five hundred forty-five thousand, six hundred sixty-four".