149781221 has 4 divisors (see below), whose sum is σ = 156293472. Its totient is φ = 143268972.

The previous prime is 149781209. The next prime is 149781223. The reversal of 149781221 is 122187941.

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: 122187941 = 61 ⋅2003081.

It is a cyclic number.

It is not a de Polignac number, because 149781221 - 2¹⁴ = 149764837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (149781223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3256091 + ... + 3256136.

It is an arithmetic number, because the mean of its divisors is an integer number (39073368).

Almost surely, 2^149781221 is an apocalyptic number.

It is an amenable number.

149781221 is a deficient number, since it is larger than the sum of its proper divisors (6512251).

149781221 is an equidigital number, since it uses as much as digits as its factorization.

149781221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6512250.

The product of its digits is 8064, while the sum is 35.

The square root of 149781221 is about 12238.5138395150. The cubic root of 149781221 is about 531.0708395908.

The spelling of 149781221 in words is "one hundred forty-nine million, seven hundred eighty-one thousand, two hundred twenty-one".