154507991 has 4 divisors (see below), whose sum is σ = 168554184. Its totient is φ = 140461800.

The previous prime is 154507979. The next prime is 154507993. The reversal of 154507991 is 199705451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199705451 = 11 ⋅18155041.

It is a cyclic number.

It is not a de Polignac number, because 154507991 - 2²² = 150313687 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 (154507993) 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, 7023080 + ... + 7023101.

It is an arithmetic number, because the mean of its divisors is an integer number (42138546).

Almost surely, 2^154507991 is an apocalyptic number.

154507991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

154507991 is a deficient number, since it is larger than the sum of its proper divisors (14046193).

154507991 is a wasteful number, since it uses less digits than its factorization.

154507991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14046192.

The product of its (nonzero) digits is 56700, while the sum is 41.

The square root of 154507991 is about 12430.1243356613. The cubic root of 154507991 is about 536.5995636859.

The spelling of 154507991 in words is "one hundred fifty-four million, five hundred seven thousand, nine hundred ninety-one".