21100673664 has 384 divisors, whose sum is σ = 72473856000. Its totient is φ = 5986151424.

The previous prime is 21100673647. The next prime is 21100673689. The reversal of 21100673664 is 46637600112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (384).

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 43327629 + ... + 43328115.

It is an arithmetic number, because the mean of its divisors is an integer number (188734000).

Almost surely, 2^21100673664 is an apocalyptic number.

21100673664 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 21100673664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36236928000).

21100673664 is an abundant number, since it is smaller than the sum of its proper divisors (51373182336).

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

21100673664 is an equidigital number, since it uses as much as digits as its factorization.

21100673664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 722 (or 698 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The spelling of 21100673664 in words is "twenty-one billion, one hundred million, six hundred seventy-three thousand, six hundred sixty-four".