21079376640 has 648 divisors, whose sum is σ = 85878046800. Its totient is φ = 4759437312.

The previous prime is 21079376639. The next prime is 21079376657. The reversal of 21079376640 is 4667397012.

21079376640 is a `hidden beast` number, since 210 + 7 + 9 + 376 + 64 + 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, 60399186 + ... + 60399534.

It is an arithmetic number, because the mean of its divisors is an integer number (132527850).

Almost surely, 2^21079376640 is an apocalyptic number.

21079376640 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 21079376640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42939023400).

21079376640 is an abundant number, since it is smaller than the sum of its proper divisors (64798670160).

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

21079376640 is a wasteful number, since it uses less digits than its factorization.

21079376640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497 (or 473 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The spelling of 21079376640 in words is "twenty-one billion, seventy-nine million, three hundred seventy-six thousand, six hundred forty".