17981971 has 12 divisors (see below), whose sum is σ = 22149288. Its totient is φ = 14505792.

The previous prime is 17981969. The next prime is 17981981. The reversal of 17981971 is 17918971.

It is not a de Polignac number, because 17981971 - 2¹ = 17981969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (17981981) 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, 9961 + ... + 11626.

It is an arithmetic number, because the mean of its divisors is an integer number (1845774).

Almost surely, 2^17981971 is an apocalyptic number.

17981971 is a deficient number, since it is larger than the sum of its proper divisors (4167317).

17981971 is a wasteful number, since it uses less digits than its factorization.

17981971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21618 (or 21611 counting only the distinct ones).

The product of its digits is 31752, while the sum is 43.

The square root of 17981971 is about 4240.5154167860. The cubic root of 17981971 is about 261.9866114014.

The spelling of 17981971 in words is "seventeen million, nine hundred eighty-one thousand, nine hundred seventy-one".