157821197 has 2 divisors, whose sum is σ = 157821198. Its totient is φ = 157821196.

The previous prime is 157821187. The next prime is 157821203. The reversal of 157821197 is 791128751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135815716 + 22005481 = 11654^2 + 4691^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157821197 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157821107) 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, 78910598 + 78910599.

It is an arithmetic number, because the mean of its divisors is an integer number (78910599).

Almost surely, 2^157821197 is an apocalyptic number.

It is an amenable number.

157821197 is a deficient number, since it is larger than the sum of its proper divisors (1).

157821197 is an equidigital number, since it uses as much as digits as its factorization.

157821197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35280, while the sum is 41.

The square root of 157821197 is about 12562.6906751699. The cubic root of 157821197 is about 540.4080101132.

The spelling of 157821197 in words is "one hundred fifty-seven million, eight hundred twenty-one thousand, one hundred ninety-seven".