180405981 has 24 divisors (see below), whose sum is σ = 305762240. Its totient is φ = 102983616.

The previous prime is 180405977. The next prime is 180405983. The reversal of 180405981 is 189504081.

180405981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 180405981 - 2² = 180405977 is a prime.

It is a super-2 number, since 2×180405981² = 65092635961144722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (180405983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 184165 + ... + 185141.

Almost surely, 2^180405981 is an apocalyptic number.

It is an amenable number.

180405981 is a deficient number, since it is larger than the sum of its proper divisors (125356259).

180405981 is an frugal number, since it uses more digits than its factorization.

180405981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970 (or 987 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 180405981 is about 13431.5293619156. The cubic root of 180405981 is about 565.0457905301.

The spelling of 180405981 in words is "one hundred eighty million, four hundred five thousand, nine hundred eighty-one".