21347391744 has 324 divisors, whose sum is σ = 72078489756. Its totient is φ = 6058450944.

The previous prime is 21347391733. The next prime is 21347391797. The reversal of 21347391744 is 44719374312.

21347391744 is a `hidden beast` number, since 2 + 1 + 3 + 473 + 9 + 174 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20391840000 + 955551744 = 142800^2 + 30912^2 .

It is a super-2 number, since 2×21347391744² (a number of 21 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21347391744.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 19530462 + ... + 19531554.

Almost surely, 2^21347391744 is an apocalyptic number.

21347391744 is a gapful number since it is divisible by the number (24) 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 21347391744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36039244878).

21347391744 is an abundant number, since it is smaller than the sum of its proper divisors (50731098012).

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

21347391744 is a wasteful number, since it uses less digits than its factorization.

21347391744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1302 (or 1278 counting only the distinct ones).

The product of its digits is 508032, while the sum is 45.

The spelling of 21347391744 in words is "twenty-one billion, three hundred forty-seven million, three hundred ninety-one thousand, seven hundred forty-four".