21139854128640 has 1280 divisors, whose sum is σ = 82545756733440. Its totient is φ = 5160425324544.

The previous prime is 21139854128573. The next prime is 21139854128669. The reversal of 21139854128640 is 4682145893112.

21139854128640 is a `hidden beast` number, since 2 + 1 + 1 + 3 + 98 + 541 + 2 + 8 + 6 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1280).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 9243485577 + ... + 9243487863.

It is an arithmetic number, because the mean of its divisors is an integer number (64488872448).

Almost surely, 2^{21139854128640} is an apocalyptic number.

21139854128640 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 21139854128640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41272878366720).

21139854128640 is an abundant number, since it is smaller than the sum of its proper divisors (61405902604800).

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

21139854128640 is an equidigital number, since it uses as much as digits as its factorization.

21139854128640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2471 (or 2437 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 54.

The spelling of 21139854128640 in words is "twenty-one trillion, one hundred thirty-nine billion, eight hundred fifty-four million, one hundred twenty-eight thousand, six hundred forty".