157778431 has 4 divisors (see below), whose sum is σ = 158100264. Its totient is φ = 157456600.

The previous prime is 157778429. The next prime is 157778441. The reversal of 157778431 is 134877751.

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: 134877751 = 19 ⋅7098829.

It is a cyclic number.

It is not a de Polignac number, because 157778431 - 2¹ = 157778429 is a prime.

It is a super-2 number, since 2×157778431² = 49788066577643522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157778441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160180 + ... + 161161.

It is an arithmetic number, because the mean of its divisors is an integer number (39525066).

Almost surely, 2^157778431 is an apocalyptic number.

157778431 is a deficient number, since it is larger than the sum of its proper divisors (321833).

157778431 is an equidigital number, since it uses as much as digits as its factorization.

157778431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321832.

The product of its digits is 164640, while the sum is 43.

The square root of 157778431 is about 12560.9884563278. The cubic root of 157778431 is about 540.3591928921.

It can be divided in two parts, 1577 and 78431, that added together give a palindrome (80008).

The spelling of 157778431 in words is "one hundred fifty-seven million, seven hundred seventy-eight thousand, four hundred thirty-one".