157998999 has 4 divisors (see below), whose sum is σ = 210665336. Its totient is φ = 105332664.

The previous prime is 157998979. The next prime is 157999021. The reversal of 157998999 is 999899751.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 999899751 = 3 ⋅333299917.

It is not a de Polignac number, because 157998999 - 2⁹ = 157998487 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 (157998959) 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, 26333164 + ... + 26333169.

It is an arithmetic number, because the mean of its divisors is an integer number (52666334).

Almost surely, 2^157998999 is an apocalyptic number.

157998999 is a deficient number, since it is larger than the sum of its proper divisors (52666337).

157998999 is an equidigital number, since it uses as much as digits as its factorization.

157998999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52666336.

The product of its digits is 16533720, while the sum is 66.

The square root of 157998999 is about 12569.7652722714. The cubic root of 157998999 is about 540.6108759004.

The spelling of 157998999 in words is "one hundred fifty-seven million, nine hundred ninety-eight thousand, nine hundred ninety-nine".