151981891 has 4 divisors (see below), whose sum is σ = 152139384. Its totient is φ = 151824400.

The previous prime is 151981883. The next prime is 151981897. The reversal of 151981891 is 198189151.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198189151 = 6379 ⋅31069.

It is a cyclic number.

It is not a de Polignac number, because 151981891 - 2³ = 151981883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (151981897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77290 + ... + 79231.

It is an arithmetic number, because the mean of its divisors is an integer number (38034846).

Almost surely, 2^151981891 is an apocalyptic number.

151981891 is a deficient number, since it is larger than the sum of its proper divisors (157493).

151981891 is an equidigital number, since it uses as much as digits as its factorization.

151981891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157492.

The product of its digits is 25920, while the sum is 43.

The square root of 151981891 is about 12328.0935671336. The cubic root of 151981891 is about 533.6591350055.

The spelling of 151981891 in words is "one hundred fifty-one million, nine hundred eighty-one thousand, eight hundred ninety-one".