149681 has 4 divisors (see below), whose sum is σ = 171072. Its totient is φ = 128292.

The previous prime is 149629. The next prime is 149689. The reversal of 149681 is 186941.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 186941 = 19 ⋅9839.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-149681 is a prime.

It is a super-2 number, since 2×149681² = 44808803522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (149689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10685 + ... + 10698.

It is an arithmetic number, because the mean of its divisors is an integer number (42768).

2¹⁴⁹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

149681 is a deficient number, since it is larger than the sum of its proper divisors (21391).

149681 is an equidigital number, since it uses as much as digits as its factorization.

149681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21390.

The product of its digits is 1728, while the sum is 29.

The square root of 149681 is about 386.8862882037. The cubic root of 149681 is about 53.0952363844.

The spelling of 149681 in words is "one hundred forty-nine thousand, six hundred eighty-one".