21397493514240 has 624 divisors, whose sum is σ = 76381697253888. Its totient is φ = 5537286586368.

The previous prime is 21397493514109. The next prime is 21397493514259. The reversal of 21397493514240 is 4241539479312.

21397493514240 is a `hidden beast` number, since 2 + 1 + 3 + 9 + 7 + 49 + 351 + 4 + 240 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55868129089 + ... + 55868129471.

It is an arithmetic number, because the mean of its divisors is an integer number (122406566112).

Almost surely, 2^{21397493514240} is an apocalyptic number.

21397493514240 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 21397493514240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38190848626944).

21397493514240 is an abundant number, since it is smaller than the sum of its proper divisors (54984203739648).

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

21397493514240 is an frugal number, since it uses more digits than its factorization.

21397493514240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 54.

The spelling of 21397493514240 in words is "twenty-one trillion, three hundred ninety-seven billion, four hundred ninety-three million, five hundred fourteen thousand, two hundred forty".