21782634660 has 36 divisors (see below), whose sum is σ = 66073992348. Its totient is φ = 5808702528.

The previous prime is 21782634649. The next prime is 21782634673. The reversal of 21782634660 is 6643628712.

21782634660 is a `hidden beast` number, since 2 + 1 + 7 + 8 + 2 + 634 + 6 + 6 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2258720676 + 19523913984 = 47526^2 + 139728^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60507139 + ... + 60507498.

Almost surely, 2^21782634660 is an apocalyptic number.

21782634660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21782634660 is an abundant number, since it is smaller than the sum of its proper divisors (44291357688).

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

21782634660 is a wasteful number, since it uses less digits than its factorization.

21782634660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121014652 (or 121014647 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 45.

The spelling of 21782634660 in words is "twenty-one billion, seven hundred eighty-two million, six hundred thirty-four thousand, six hundred sixty".