151878991 has 4 divisors (see below), whose sum is σ = 165686184. Its totient is φ = 138071800.

The previous prime is 151878941. The next prime is 151878997. The reversal of 151878991 is 199878151.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 151878991 - 2⁷ = 151878863 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 (151878997) 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, 6903580 + ... + 6903601.

It is an arithmetic number, because the mean of its divisors is an integer number (41421546).

Almost surely, 2^151878991 is an apocalyptic number.

151878991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

151878991 is a deficient number, since it is larger than the sum of its proper divisors (13807193).

151878991 is a wasteful number, since it uses less digits than its factorization.

151878991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13807192.

The product of its digits is 181440, while the sum is 49.

The square root of 151878991 is about 12323.9194658193. The cubic root of 151878991 is about 533.5386690684.

The spelling of 151878991 in words is "one hundred fifty-one million, eight hundred seventy-eight thousand, nine hundred ninety-one".