7981990 has 8 divisors (see below), whose sum is σ = 14367600. Its totient is φ = 3192792.

The previous prime is 7981949. The next prime is 7981999. The reversal of 7981990 is 991897.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7981999) 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, 399090 + ... + 399109.

It is an arithmetic number, because the mean of its divisors is an integer number (1795950).

Almost surely, 2^7981990 is an apocalyptic number.

7981990 is a deficient number, since it is larger than the sum of its proper divisors (6385610).

7981990 is a wasteful number, since it uses less digits than its factorization.

7981990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798206.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 7981990 is about 2825.2415825908. The cubic root of 7981990 is about 199.8498039006.

The spelling of 7981990 in words is "seven million, nine hundred eighty-one thousand, nine hundred ninety".