7721476221 has 4 divisors (see below), whose sum is σ = 10295301632. Its totient is φ = 5147650812.

The previous prime is 7721476219. The next prime is 7721476223. The reversal of 7721476221 is 1226741277.

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 an interprime number because it is at equal distance from previous prime (7721476219) and next prime (7721476223).

It is not a de Polignac number, because 7721476221 - 2¹ = 7721476219 is a prime.

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 7721476221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7721476223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1286912701 + ... + 1286912706.

It is an arithmetic number, because the mean of its divisors is an integer number (2573825408).

Almost surely, 2^7721476221 is an apocalyptic number.

It is an amenable number.

7721476221 is a deficient number, since it is larger than the sum of its proper divisors (2573825411).

7721476221 is a wasteful number, since it uses less digits than its factorization.

7721476221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2573825410.

The product of its digits is 65856, while the sum is 39.

The square root of 7721476221 is about 87871.9307913511. The cubic root of 7721476221 is about 1976.5149916969.

The spelling of 7721476221 in words is "seven billion, seven hundred twenty-one million, four hundred seventy-six thousand, two hundred twenty-one".