8453201538721 has 9 divisors (see below), whose sum is σ = 8483005404979. Its totient is φ = 8423502049336.

The previous prime is 8453201538713. The next prime is 8453201538779. The reversal of 8453201538721 is 1278351023548.

The square root of 8453201538721 is 2907439.

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., 7997895083025 + 455306455696 = 2828055^2 + 674764^2 .

It is not a de Polignac number, because 8453201538721 - 2³ = 8453201538713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8453201538421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 851874666 + ... + 851884588.

Almost surely, 2^{8453201538721} is an apocalyptic number.

8453201538721 is the 2907439-th square number.

8453201538721 is the 1453720-th centered octagonal number.

It is an amenable number.

8453201538721 is a deficient number, since it is larger than the sum of its proper divisors (29803866258).

8453201538721 is an frugal number, since it uses more digits than its factorization.

8453201538721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20432 (or 10216 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 49.

Multiplying 8453201538721 by its sum of digits (49), we get a square (414206875397329 = 20352073²).

The spelling of 8453201538721 in words is "eight trillion, four hundred fifty-three billion, two hundred one million, five hundred thirty-eight thousand, seven hundred twenty-one".