126509989 has 2 divisors, whose sum is σ = 126509990. Its totient is φ = 126509988.

The previous prime is 126509987. The next prime is 126510023. The reversal of 126509989 is 989905621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125821089 + 688900 = 11217^2 + 830^2 .

It is a cyclic number.

It is not a de Polignac number, because 126509989 - 2¹ = 126509987 is a prime.

Together with 126509987, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126509987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63254994 + 63254995.

It is an arithmetic number, because the mean of its divisors is an integer number (63254995).

Almost surely, 2^126509989 is an apocalyptic number.

It is an amenable number.

126509989 is a deficient number, since it is larger than the sum of its proper divisors (1).

126509989 is an equidigital number, since it uses as much as digits as its factorization.

126509989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 349920, while the sum is 49.

The square root of 126509989 is about 11247.6659356508. The cubic root of 126509989 is about 502.0052657342.

The spelling of 126509989 in words is "one hundred twenty-six million, five hundred nine thousand, nine hundred eighty-nine".