7667721 has 12 divisors (see below), whose sum is σ = 11311872. Its totient is φ = 5002776.

The previous prime is 7667719. The next prime is 7667729. The reversal of 7667721 is 1277667.

It is not a de Polignac number, because 7667721 - 2¹ = 7667719 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

7667721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (7667729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8641 + ... + 9486.

It is an arithmetic number, because the mean of its divisors is an integer number (942656).

Almost surely, 2^7667721 is an apocalyptic number.

It is an amenable number.

7667721 is a deficient number, since it is larger than the sum of its proper divisors (3644151).

7667721 is a wasteful number, since it uses less digits than its factorization.

7667721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18180 (or 18177 counting only the distinct ones).

The product of its digits is 24696, while the sum is 36.

The square root of 7667721 is about 2769.0650046541. The cubic root of 7667721 is about 197.1917618794.

The spelling of 7667721 in words is "seven million, six hundred sixty-seven thousand, seven hundred twenty-one".