149521681 has 4 divisors (see below), whose sum is σ = 158317092. Its totient is φ = 140726272.

The previous prime is 149521679. The next prime is 149521727. The reversal of 149521681 is 186125941.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186125941 = 4679 ⋅39779.

It can be written as a sum of positive squares in 2 ways, for example, as 64144081 + 85377600 = 8009^2 + 9240^2 .

It is not a de Polignac number, because 149521681 - 2¹ = 149521679 is a prime.

It is a super-2 number, since 2×149521681² = 44713466178131522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 149521681.

It is not an unprimeable number, because it can be changed into a prime (149521661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4397680 + ... + 4397713.

It is an arithmetic number, because the mean of its divisors is an integer number (39579273).

Almost surely, 2^149521681 is an apocalyptic number.

It is an amenable number.

149521681 is a deficient number, since it is larger than the sum of its proper divisors (8795411).

149521681 is an equidigital number, since it uses as much as digits as its factorization.

149521681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8795410.

The product of its digits is 17280, while the sum is 37.

The square root of 149521681 is about 12227.9058305173. The cubic root of 149521681 is about 530.7639167909.

The spelling of 149521681 in words is "one hundred forty-nine million, five hundred twenty-one thousand, six hundred eighty-one".