157798409 has 2 divisors, whose sum is σ = 157798410. Its totient is φ = 157798408.

The previous prime is 157798397. The next prime is 157798447. The reversal of 157798409 is 904897751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 146047225 + 11751184 = 12085^2 + 3428^2 .

It is an emirp because it is prime and its reverse (904897751) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157798409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (157798609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78899204 + 78899205.

It is an arithmetic number, because the mean of its divisors is an integer number (78899205).

Almost surely, 2^157798409 is an apocalyptic number.

It is an amenable number.

157798409 is a deficient number, since it is larger than the sum of its proper divisors (1).

157798409 is an equidigital number, since it uses as much as digits as its factorization.

157798409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 635040, while the sum is 50.

The square root of 157798409 is about 12561.7836711193. The cubic root of 157798409 is about 540.3819987984.

The spelling of 157798409 in words is "one hundred fifty-seven million, seven hundred ninety-eight thousand, four hundred nine".