21149765760 has 128 divisors (see below), whose sum is σ = 67547468160. Its totient is φ = 5628846080.

The previous prime is 21149765753. The next prime is 21149765761. The reversal of 21149765760 is 6756794112.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21149765761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 989749 + ... + 1010891.

It is an arithmetic number, because the mean of its divisors is an integer number (527714595).

Almost surely, 2^21149765760 is an apocalyptic number.

21149765760 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 21149765760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33773734080).

21149765760 is an abundant number, since it is smaller than the sum of its proper divisors (46397702400).

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

21149765760 is a wasteful number, since it uses less digits than its factorization.

21149765760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21686 (or 21674 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 48.

The spelling of 21149765760 in words is "twenty-one billion, one hundred forty-nine million, seven hundred sixty-five thousand, seven hundred sixty".