149555981 has 2 divisors, whose sum is σ = 149555982. Its totient is φ = 149555980.

The previous prime is 149555977. The next prime is 149556037. The reversal of 149555981 is 189555941.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135373225 + 14182756 = 11635^2 + 3766^2 .

It is a cyclic number.

It is not a de Polignac number, because 149555981 - 2² = 149555977 is a prime.

It is a super-2 number, since 2×149555981² = 44733982905744722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (149555921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74777990 + 74777991.

It is an arithmetic number, because the mean of its divisors is an integer number (74777991).

Almost surely, 2^149555981 is an apocalyptic number.

It is an amenable number.

149555981 is a deficient number, since it is larger than the sum of its proper divisors (1).

149555981 is an equidigital number, since it uses as much as digits as its factorization.

149555981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324000, while the sum is 47.

The square root of 149555981 is about 12229.3082797025. The cubic root of 149555981 is about 530.8044991117.

The spelling of 149555981 in words is "one hundred forty-nine million, five hundred fifty-five thousand, nine hundred eighty-one".