126561209 has 8 divisors (see below), whose sum is σ = 134188488. Its totient is φ = 118954240.

The previous prime is 126561199. The next prime is 126561217. The reversal of 126561209 is 902165621.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 21949225 + 104611984 = 4685^2 + 10228^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 126561209 - 2¹² = 126557113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126561269) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8879 + ... + 18219.

It is an arithmetic number, because the mean of its divisors is an integer number (16773561).

Almost surely, 2^126561209 is an apocalyptic number.

It is an amenable number.

126561209 is a deficient number, since it is larger than the sum of its proper divisors (7627279).

126561209 is an equidigital number, since it uses as much as digits as its factorization.

126561209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10155.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 126561209 is about 11249.9426220759. The cubic root of 126561209 is about 502.0730054192.

The spelling of 126561209 in words is "one hundred twenty-six million, five hundred sixty-one thousand, two hundred nine".