21139634880 has 1344 divisors, whose sum is σ = 98070497280. Its totient is φ = 4240760832.

The previous prime is 21139634869. The next prime is 21139634899. The reversal of 21139634880 is 8843693112.

21139634880 is a `hidden beast` number, since 2 + 1 + 1 + 3 + 9 + 634 + 8 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a super-2 number, since 2×21139634880² (a number of 21 digits) contains 22 as substring.

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 191 ways as a sum of consecutive naturals, for example, 126584557 + ... + 126584723.

It is an arithmetic number, because the mean of its divisors is an integer number (72969120).

Almost surely, 2^21139634880 is an apocalyptic number.

21139634880 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 21139634880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49035248640).

21139634880 is an abundant number, since it is smaller than the sum of its proper divisors (76930862400).

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

21139634880 is a wasteful number, since it uses less digits than its factorization.

21139634880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 21139634880 in words is "twenty-one billion, one hundred thirty-nine million, six hundred thirty-four thousand, eight hundred eighty".