20257299657721 has 9 divisors (see below), whose sum is σ = 23564650537071. Its totient is φ = 17363372701752.

The previous prime is 20257299657653. The next prime is 20257299657787. The reversal of 20257299657721 is 12775699275202.

The square root of 20257299657721 is 4500811.

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., 7379508075625 + 12877791582096 = 2716525^2 + 3588564^2 .

It is not a de Polignac number, because 20257299657721 - 2²³ = 20257291269113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20257299657521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 31184191 + ... + 31827163.

It is an arithmetic number, because the mean of its divisors is an integer number (2618294504119).

Almost surely, 2^{20257299657721} is an apocalyptic number.

20257299657721 is the 4500811-st square number.

20257299657721 is the 2250406-th centered octagonal number.

It is an amenable number.

20257299657721 is a deficient number, since it is larger than the sum of its proper divisors (3307350879350).

20257299657721 is an frugal number, since it uses more digits than its factorization.

20257299657721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1285960 (or 642980 counting only the distinct ones).

The product of its (nonzero) digits is 66679200, while the sum is 64.

The spelling of 20257299657721 in words is "twenty trillion, two hundred fifty-seven billion, two hundred ninety-nine million, six hundred fifty-seven thousand, seven hundred twenty-one".