149656581 has 12 divisors (see below), whose sum is σ = 216387808. Its totient is φ = 99670824.

The previous prime is 149656579. The next prime is 149656613. The reversal of 149656581 is 185656941.

149656581 is a `hidden beast` number, since 1 + 4 + 9 + 6 + 565 + 81 = 666.

It is not a de Polignac number, because 149656581 - 2¹ = 149656579 is a prime.

It is a super-2 number, since 2×149656581² = 44794184473219122, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (149656511) 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, 1746 + ... + 17388.

Almost surely, 2^149656581 is an apocalyptic number.

It is an amenable number.

149656581 is a deficient number, since it is larger than the sum of its proper divisors (66731227).

149656581 is a wasteful number, since it uses less digits than its factorization.

149656581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16712 (or 16709 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The square root of 149656581 is about 12233.4206581806. The cubic root of 149656581 is about 530.9234890347.

The spelling of 149656581 in words is "one hundred forty-nine million, six hundred fifty-six thousand, five hundred eighty-one".