21049507680 has 96 divisors (see below), whose sum is σ = 66542339808. Its totient is φ = 5593190400.

The previous prime is 21049507679. The next prime is 21049507711. The reversal of 21049507680 is 8670594012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56850 + ... + 212910.

It is an arithmetic number, because the mean of its divisors is an integer number (693149373).

Almost surely, 2^21049507680 is an apocalyptic number.

21049507680 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 21049507680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33271169904).

21049507680 is an abundant number, since it is smaller than the sum of its proper divisors (45492832128).

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

21049507680 is a wasteful number, since it uses less digits than its factorization.

21049507680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156360 (or 156352 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 42.

The spelling of 21049507680 in words is "twenty-one billion, forty-nine million, five hundred seven thousand, six hundred eighty".