7921990 has 16 divisors (see below), whose sum is σ = 14408352. Its totient is φ = 3135744.

The previous prime is 7921987. The next prime is 7921999. The reversal of 7921990 is 991297.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7921999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3114 + ... + 5053.

It is an arithmetic number, because the mean of its divisors is an integer number (900522).

Almost surely, 2^7921990 is an apocalyptic number.

7921990 is a deficient number, since it is larger than the sum of its proper divisors (6486362).

7921990 is a wasteful number, since it uses less digits than its factorization.

7921990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8271.

The product of its (nonzero) digits is 10206, while the sum is 37.

The square root of 7921990 is about 2814.6029915425. The cubic root of 7921990 is about 199.3477921029.

It can be divided in two parts, 7921 and 990, that added together give a triangular number (8911 = T₁₃₃).

The spelling of 7921990 in words is "seven million, nine hundred twenty-one thousand, nine hundred ninety".