157442821 has 2 divisors, whose sum is σ = 157442822. Its totient is φ = 157442820.

The previous prime is 157442819. The next prime is 157442833. The reversal of 157442821 is 128244751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138909796 + 18533025 = 11786^2 + 4305^2 .

It is a cyclic number.

It is not a de Polignac number, because 157442821 - 2¹ = 157442819 is a prime.

Together with 157442819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157442861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78721410 + 78721411.

It is an arithmetic number, because the mean of its divisors is an integer number (78721411).

Almost surely, 2^157442821 is an apocalyptic number.

It is an amenable number.

157442821 is a deficient number, since it is larger than the sum of its proper divisors (1).

157442821 is an equidigital number, since it uses as much as digits as its factorization.

157442821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17920, while the sum is 34.

The square root of 157442821 is about 12547.6221253272. The cubic root of 157442821 is about 539.9757888093.

The spelling of 157442821 in words is "one hundred fifty-seven million, four hundred forty-two thousand, eight hundred twenty-one".