21061877760 has 1080 divisors, whose sum is σ = 94401989136. Its totient is φ = 4293918720.

The previous prime is 21061877737. The next prime is 21061877797. The reversal of 21061877760 is 6777816012.

21061877760 is a `hidden beast` number, since 21 + 0 + 618 + 7 + 7 + 7 + 6 + 0 = 666.

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 71 ways as a sum of consecutive naturals, for example, 397393894 + ... + 397393946.

Almost surely, 2^21061877760 is an apocalyptic number.

21061877760 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 21061877760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47200994568).

21061877760 is an abundant number, since it is smaller than the sum of its proper divisors (73340111376).

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

21061877760 is a wasteful number, since it uses less digits than its factorization.

21061877760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 197568, while the sum is 45.

The spelling of 21061877760 in words is "twenty-one billion, sixty-one million, eight hundred seventy-seven thousand, seven hundred sixty".