157991273 has 6 divisors (see below), whose sum is σ = 173659962. Its totient is φ = 143628320.

The previous prime is 157991261. The next prime is 157991279. The reversal of 157991273 is 372199751.

It can be written as a sum of positive squares in only one way, i.e., 149621824 + 8369449 = 12232^2 + 2893^2 .

It is not a de Polignac number, because 157991273 - 2¹⁰ = 157990249 is a prime.

It is a super-2 number, since 2×157991273² = 49922484688321058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (157991279) 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 5 ways as a sum of consecutive naturals, for example, 652736 + ... + 652977.

It is an arithmetic number, because the mean of its divisors is an integer number (28943327).

Almost surely, 2^157991273 is an apocalyptic number.

It is an amenable number.

157991273 is a deficient number, since it is larger than the sum of its proper divisors (15668689).

157991273 is a wasteful number, since it uses less digits than its factorization.

157991273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1305735 (or 1305724 counting only the distinct ones).

The product of its digits is 119070, while the sum is 44.

The square root of 157991273 is about 12569.4579437619. The cubic root of 157991273 is about 540.6020639718.

The spelling of 157991273 in words is "one hundred fifty-seven million, nine hundred ninety-one thousand, two hundred seventy-three".