126691657 has 2 divisors, whose sum is σ = 126691658. Its totient is φ = 126691656.

The previous prime is 126691597. The next prime is 126691739. The reversal of 126691657 is 756196621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111175936 + 15515721 = 10544^2 + 3939^2 .

It is an emirp because it is prime and its reverse (756196621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126691657 - 2¹⁹ = 126167369 is a prime.

It is not a weakly prime, because it can be changed into another prime (126691057) 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, 63345828 + 63345829.

It is an arithmetic number, because the mean of its divisors is an integer number (63345829).

Almost surely, 2^126691657 is an apocalyptic number.

It is an amenable number.

126691657 is a deficient number, since it is larger than the sum of its proper divisors (1).

126691657 is an equidigital number, since it uses as much as digits as its factorization.

126691657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 43.

The square root of 126691657 is about 11255.7388473614. The cubic root of 126691657 is about 502.2454435379.

The spelling of 126691657 in words is "one hundred twenty-six million, six hundred ninety-one thousand, six hundred fifty-seven".