7921906 has 8 divisors (see below), whose sum is σ = 11959020. Its totient is φ = 3935568.

The previous prime is 7921891. The next prime is 7921909. The reversal of 7921906 is 6091297.

It can be written as a sum of positive squares in 2 ways, for example, as 6838225 + 1083681 = 2615^2 + 1041^2 .

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

It is not an unprimeable number, because it can be changed into a prime (7921909) 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, 12301 + ... + 12928.

Almost surely, 2^7921906 is an apocalyptic number.

7921906 is a deficient number, since it is larger than the sum of its proper divisors (4037114).

7921906 is a wasteful number, since it uses less digits than its factorization.

7921906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25388.

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 7921906 is about 2814.5880693274. The cubic root of 7921906 is about 199.3470875125.

Subtracting from 7921906 its reverse (6091297), we obtain a square (1830609 = 1353²).

The spelling of 7921906 in words is "seven million, nine hundred twenty-one thousand, nine hundred six".