7904721 has 16 divisors (see below), whose sum is σ = 11870208. Its totient is φ = 4635600.

The previous prime is 7904719. The next prime is 7904723. The reversal of 7904721 is 1274097.

7904721 = T₂₁ + T₂₂ + ... + T₃₆₁.

It is an interprime number because it is at equal distance from previous prime (7904719) and next prime (7904723).

It is not a de Polignac number, because 7904721 - 2¹ = 7904719 is a prime.

It is a super-2 number, since 2×7904721² = 124969228175682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7904723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2841 + ... + 4886.

It is an arithmetic number, because the mean of its divisors is an integer number (741888).

Almost surely, 2^7904721 is an apocalyptic number.

It is an amenable number.

7904721 is a deficient number, since it is larger than the sum of its proper divisors (3965487).

7904721 is a wasteful number, since it uses less digits than its factorization.

7904721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7772.

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

The square root of 7904721 is about 2811.5335672903. The cubic root of 7904721 is about 199.2028351962.

The spelling of 7904721 in words is "seven million, nine hundred four thousand, seven hundred twenty-one".