5172257721 has 4 divisors (see below), whose sum is σ = 6896343632. Its totient is φ = 3448171812.

The previous prime is 5172257719. The next prime is 5172257737. The reversal of 5172257721 is 1277522715.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 5172257721 - 2¹ = 5172257719 is a prime.

It is a super-2 number, since 2×5172257721² = 53504499864888227682, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5172257721.

It is not an unprimeable number, because it can be changed into a prime (5172257521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 862042951 + ... + 862042956.

It is an arithmetic number, because the mean of its divisors is an integer number (1724085908).

Almost surely, 2^5172257721 is an apocalyptic number.

It is an amenable number.

5172257721 is a deficient number, since it is larger than the sum of its proper divisors (1724085911).

5172257721 is a wasteful number, since it uses less digits than its factorization.

5172257721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1724085910.

The product of its digits is 68600, while the sum is 39.

The square root of 5172257721 is about 71918.4101673556. The cubic root of 5172257721 is about 1729.3917606288.

The spelling of 5172257721 in words is "five billion, one hundred seventy-two million, two hundred fifty-seven thousand, seven hundred twenty-one".