156681493 has 2 divisors, whose sum is σ = 156681494. Its totient is φ = 156681492.

The previous prime is 156681431. The next prime is 156681559. The reversal of 156681493 is 394186651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99860049 + 56821444 = 9993^2 + 7538^2 .

It is a cyclic number.

It is not a de Polignac number, because 156681493 - 2⁹ = 156680981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156681193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78340746 + 78340747.

It is an arithmetic number, because the mean of its divisors is an integer number (78340747).

Almost surely, 2^156681493 is an apocalyptic number.

It is an amenable number.

156681493 is a deficient number, since it is larger than the sum of its proper divisors (1).

156681493 is an equidigital number, since it uses as much as digits as its factorization.

156681493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 43.

The square root of 156681493 is about 12517.2478205075. The cubic root of 156681493 is about 539.1040160080.

It can be divided in two parts, 15668 and 1493, that added together give a square (17161 = 131²).

The spelling of 156681493 in words is "one hundred fifty-six million, six hundred eighty-one thousand, four hundred ninety-three".