126640289 has 4 divisors (see below), whose sum is σ = 129585456. Its totient is φ = 123695124.

The previous prime is 126640279. The next prime is 126640309. The reversal of 126640289 is 982046621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 126640289 - 2⁴ = 126640273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126640229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1472519 + ... + 1472604.

It is an arithmetic number, because the mean of its divisors is an integer number (32396364).

Almost surely, 2^126640289 is an apocalyptic number.

It is an amenable number.

126640289 is a deficient number, since it is larger than the sum of its proper divisors (2945167).

126640289 is an equidigital number, since it uses as much as digits as its factorization.

126640289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2945166.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 126640289 is about 11253.4567578145. The cubic root of 126640289 is about 502.1775547435.

The spelling of 126640289 in words is "one hundred twenty-six million, six hundred forty thousand, two hundred eighty-nine".