149209891 has 4 divisors (see below), whose sum is σ = 149234400. Its totient is φ = 149185384.

The previous prime is 149209877. The next prime is 149209903. The reversal of 149209891 is 198902941.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-149209891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (149209811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4665 + ... + 17893.

It is an arithmetic number, because the mean of its divisors is an integer number (37308600).

Almost surely, 2^149209891 is an apocalyptic number.

149209891 is a deficient number, since it is larger than the sum of its proper divisors (24509).

149209891 is a wasteful number, since it uses less digits than its factorization.

149209891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24508.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 149209891 is about 12215.1500604782. The cubic root of 149209891 is about 530.3947350083.

The spelling of 149209891 in words is "one hundred forty-nine million, two hundred nine thousand, eight hundred ninety-one".