157821431 has 2 divisors, whose sum is σ = 157821432. Its totient is φ = 157821430.

The previous prime is 157821383. The next prime is 157821463. The reversal of 157821431 is 134128751.

It is an a-pointer prime, because the next prime (157821463) can be obtained adding 157821431 to its sum of digits (32).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 157821431 - 2¹⁸ = 157559287 is a prime.

It is a super-2 number, since 2×157821431² = 49815208165775522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157821491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78910715 + 78910716.

It is an arithmetic number, because the mean of its divisors is an integer number (78910716).

Almost surely, 2^157821431 is an apocalyptic number.

157821431 is a deficient number, since it is larger than the sum of its proper divisors (1).

157821431 is an equidigital number, since it uses as much as digits as its factorization.

157821431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 32.

The square root of 157821431 is about 12562.6999884579. The cubic root of 157821431 is about 540.4082771990.

The spelling of 157821431 in words is "one hundred fifty-seven million, eight hundred twenty-one thousand, four hundred thirty-one".