7981209 has 12 divisors (see below), whose sum is σ = 11614356. Its totient is φ = 5281152.

The previous prime is 7981189. The next prime is 7981223. The reversal of 7981209 is 9021897.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2985984 + 4995225 = 1728^2 + 2235^2 .

It is not a de Polignac number, because 7981209 - 2⁸ = 7980953 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7981289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2004 + ... + 4469.

It is an arithmetic number, because the mean of its divisors is an integer number (967863).

Almost surely, 2^7981209 is an apocalyptic number.

It is an amenable number.

7981209 is a deficient number, since it is larger than the sum of its proper divisors (3633147).

7981209 is a wasteful number, since it uses less digits than its factorization.

7981209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6616 (or 6613 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 7981209 is about 2825.1033609410. The cubic root of 7981209 is about 199.8432855683.

The spelling of 7981209 in words is "seven million, nine hundred eighty-one thousand, two hundred nine".