181980999 has 28 divisors (see below), whose sum is σ = 275514696. Its totient is φ = 120135312.

The previous prime is 181980983. The next prime is 181981013. The reversal of 181980999 is 999089181.

It is not a de Polignac number, because 181980999 - 2⁴ = 181980983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181980979) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 76837 + ... + 79169.

Almost surely, 2^181980999 is an apocalyptic number.

181980999 is a deficient number, since it is larger than the sum of its proper divisors (93533697).

181980999 is an equidigital number, since it uses as much as digits as its factorization.

181980999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2458 (or 2443 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 54.

The square root of 181980999 is about 13490.0333209374. The cubic root of 181980999 is about 566.6853885779.

The spelling of 181980999 in words is "one hundred eighty-one million, nine hundred eighty thousand, nine hundred ninety-nine".