21916381680 has 320 divisors, whose sum is σ = 80907678720. Its totient is φ = 5438721024.

The previous prime is 21916381583. The next prime is 21916381727. The reversal of 21916381680 is 8618361912.

21916381680 is a `hidden beast` number, since 2 + 1 + 9 + 1 + 638 + 1 + 6 + 8 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1832199 + ... + 1844121.

It is an arithmetic number, because the mean of its divisors is an integer number (252836496).

Almost surely, 2^21916381680 is an apocalyptic number.

21916381680 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 21916381680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40453839360).

21916381680 is an abundant number, since it is smaller than the sum of its proper divisors (58991297040).

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

21916381680 is a wasteful number, since it uses less digits than its factorization.

21916381680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12005 (or 11993 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 21916381680 in words is "twenty-one billion, nine hundred sixteen million, three hundred eighty-one thousand, six hundred eighty".