17981956 has 12 divisors (see below), whose sum is σ = 31516492. Its totient is φ = 8977248.

The previous prime is 17981947. The next prime is 17981959. The reversal of 17981956 is 65918971.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17505856 + 476100 = 4184^2 + 690^2 .

It is not an unprimeable number, because it can be changed into a prime (17981959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135 + ... + 5998.

Almost surely, 2^17981956 is an apocalyptic number.

It is an amenable number.

17981956 is a deficient number, since it is larger than the sum of its proper divisors (13534536).

17981956 is a wasteful number, since it uses less digits than its factorization.

17981956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6870 (or 6868 counting only the distinct ones).

The product of its digits is 136080, while the sum is 46.

The square root of 17981956 is about 4240.5136481327. The cubic root of 17981956 is about 261.9865385543.

The spelling of 17981956 in words is "seventeen million, nine hundred eighty-one thousand, nine hundred fifty-six".