7991906 has 8 divisors (see below), whose sum is σ = 12910044. Its totient is φ = 3688560.

The previous prime is 7991897. The next prime is 7991939. The reversal of 7991906 is 6091997.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6325225 + 1666681 = 2515^2 + 1291^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×7991906³ (a number of 22 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 153665 + ... + 153716.

Almost surely, 2^7991906 is an apocalyptic number.

7991906 is a deficient number, since it is larger than the sum of its proper divisors (4918138).

7991906 is a wasteful number, since it uses less digits than its factorization.

7991906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307396.

The product of its (nonzero) digits is 30618, while the sum is 41.

The square root of 7991906 is about 2826.9959320806. The cubic root of 7991906 is about 199.9325272397.

The spelling of 7991906 in words is "seven million, nine hundred ninety-one thousand, nine hundred six".