156909491 has 2 divisors, whose sum is σ = 156909492. Its totient is φ = 156909490.

The previous prime is 156909469. The next prime is 156909509. The reversal of 156909491 is 194909651.

It is a strong prime.

It is an emirp because it is prime and its reverse (194909651) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-156909491 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (156909461) 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 as a sum of consecutive naturals, namely, 78454745 + 78454746.

It is an arithmetic number, because the mean of its divisors is an integer number (78454746).

Almost surely, 2^156909491 is an apocalyptic number.

156909491 is a deficient number, since it is larger than the sum of its proper divisors (1).

156909491 is an equidigital number, since it uses as much as digits as its factorization.

156909491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 156909491 is about 12526.3518631723. The cubic root of 156909491 is about 539.3653850286.

The spelling of 156909491 in words is "one hundred fifty-six million, nine hundred nine thousand, four hundred ninety-one".