5625961791921 has 9 divisors (see below), whose sum is σ = 8126399533291. Its totient is φ = 3750636450792.

The previous prime is 5625961791881. The next prime is 5625961791943. The reversal of 5625961791921 is 1291971695265.

The square root of 5625961791921 is 2371911.

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

5625961791921 is a `hidden beast` number, since 5 + 6 + 2 + 5 + 9 + 617 + 9 + 1 + 9 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17420040225 + 5608541751696 = 131985^2 + 2368236^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 5625961791921 - 2²⁷ = 5625827574193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5625961791221) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6720415 + ... + 7511051.

Almost surely, 2^{5625961791921} is an apocalyptic number.

5625961791921 is the 2371911-st square number.

5625961791921 is the 1185956-th centered octagonal number.

It is an amenable number.

5625961791921 is a deficient number, since it is larger than the sum of its proper divisors (2500437741370).

5625961791921 is an frugal number, since it uses more digits than its factorization.

5625961791921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581280 (or 790640 counting only the distinct ones).

The product of its digits is 18370800, while the sum is 63.

The spelling of 5625961791921 in words is "five trillion, six hundred twenty-five billion, nine hundred sixty-one million, seven hundred ninety-one thousand, nine hundred twenty-one".