21801415680 has 792 divisors, whose sum is σ = 87024356640. Its totient is φ = 5195612160.

The previous prime is 21801415667. The next prime is 21801415693. The reversal of 21801415680 is 8651410812.

21801415680 is a `hidden beast` number, since 2 + 1 + 80 + 14 + 1 + 568 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21801415667) and next prime (21801415693).

It is a tau number, because it is divible by the number of its divisors (792).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 369515491 + ... + 369515549.

Almost surely, 2^21801415680 is an apocalyptic number.

21801415680 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 21801415680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43512178320).

21801415680 is an abundant number, since it is smaller than the sum of its proper divisors (65222940960).

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

21801415680 is an frugal number, since it uses more digits than its factorization.

21801415680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The spelling of 21801415680 in words is "twenty-one billion, eight hundred one million, four hundred fifteen thousand, six hundred eighty".