7668721 has 4 divisors (see below), whose sum is σ = 7675200. Its totient is φ = 7662244.

The previous prime is 7668709. The next prime is 7668757. The reversal of 7668721 is 1278667.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 7668721 - 2¹³ = 7660529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7668701) 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, 901 + ... + 4018.

It is an arithmetic number, because the mean of its divisors is an integer number (1918800).

Almost surely, 2^7668721 is an apocalyptic number.

It is an amenable number.

7668721 is a deficient number, since it is larger than the sum of its proper divisors (6479).

7668721 is a wasteful number, since it uses less digits than its factorization.

7668721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6478.

The product of its digits is 28224, while the sum is 37.

The square root of 7668721 is about 2769.2455651314. The cubic root of 7668721 is about 197.2003338827.

The spelling of 7668721 in words is "seven million, six hundred sixty-eight thousand, seven hundred twenty-one".