21597081274756 has 81 divisors (see below), whose sum is σ = 41826117438021. Its totient is φ = 9753235743264.

The previous prime is 21597081274697. The next prime is 21597081274759. The reversal of 21597081274756 is 65747218079512.

It is a happy number.

The square root of 21597081274756 is 4647266.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3194834508100 + 18402246766656 = 1787410^2 + 4289784^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21597081274759) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 5678957151 + ... + 5678960953.

Almost surely, 2^{21597081274756} is an apocalyptic number.

21597081274756 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21597081274756 is the 4647266-th square number.

It is an amenable number.

21597081274756 is a deficient number, since it is larger than the sum of its proper divisors (20229036163265).

21597081274756 is an frugal number, since it uses more digits than its factorization.

21597081274756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7730 (or 3865 counting only the distinct ones).

The product of its (nonzero) digits is 59270400, while the sum is 64.

The spelling of 21597081274756 in words is "twenty-one trillion, five hundred ninety-seven billion, eighty-one million, two hundred seventy-four thousand, seven hundred fifty-six".