21186261760 has 36 divisors (see below), whose sum is σ = 50747720688. Its totient is φ = 8474504192.

The previous prime is 21186261757. The next prime is 21186261823. The reversal of 21186261760 is 6716268112.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8274604 + ... + 8277163.

It is an arithmetic number, because the mean of its divisors is an integer number (1409658908).

Almost surely, 2^21186261760 is an apocalyptic number.

21186261760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21186261760 is an abundant number, since it is smaller than the sum of its proper divisors (29561458928).

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

21186261760 is an equidigital number, since it uses as much as digits as its factorization.

21186261760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16551788 (or 16551774 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 40.

The spelling of 21186261760 in words is "twenty-one billion, one hundred eighty-six million, two hundred sixty-one thousand, seven hundred sixty".