7940721 has 16 divisors (see below), whose sum is σ = 10869120. Its totient is φ = 5155200.

The previous prime is 7940719. The next prime is 7940747. The reversal of 7940721 is 1270497.

7940721 = 89² + 90² + ... + 290².

It is not a de Polignac number, because 7940721 - 2¹ = 7940719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7940761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21940 + ... + 22298.

It is an arithmetic number, because the mean of its divisors is an integer number (679320).

Almost surely, 2^7940721 is an apocalyptic number.

It is an amenable number.

7940721 is a deficient number, since it is larger than the sum of its proper divisors (2928399).

7940721 is a wasteful number, since it uses less digits than its factorization.

7940721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536.

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 7940721 is about 2817.9284944796. The cubic root of 7940721 is about 199.5047831467.

The spelling of 7940721 in words is "seven million, nine hundred forty thousand, seven hundred twenty-one".