7921989 has 16 divisors (see below), whose sum is σ = 11937600. Its totient is φ = 5190768.

The previous prime is 7921987. The next prime is 7921999. The reversal of 7921989 is 9891297.

7921989 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 7921989 - 2¹ = 7921987 is a prime.

It is a super-2 number, since 2×7921989² = 125515819432242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7921981) 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 15 ways as a sum of consecutive naturals, for example, 894 + ... + 4079.

It is an arithmetic number, because the mean of its divisors is an integer number (746100).

Almost surely, 2^7921989 is an apocalyptic number.

It is an amenable number.

7921989 is a deficient number, since it is larger than the sum of its proper divisors (4015611).

7921989 is a wasteful number, since it uses less digits than its factorization.

7921989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5041 (or 5035 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 7921989 is about 2814.6028138975. The cubic root of 7921989 is about 199.3477837150.

The spelling of 7921989 in words is "seven million, nine hundred twenty-one thousand, nine hundred eighty-nine".