126551561 has 4 divisors (see below), whose sum is σ = 126934224. Its totient is φ = 126168900.

The previous prime is 126551539. The next prime is 126551567. The reversal of 126551561 is 165155621.

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, and also an emirpimes, since its reverse is a distinct semiprime: 165155621 = 3469 ⋅47609.

It is a cyclic number.

It is not a de Polignac number, because 126551561 - 2¹⁴ = 126535177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126551567) 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, 190835 + ... + 191496.

It is an arithmetic number, because the mean of its divisors is an integer number (31733556).

Almost surely, 2^126551561 is an apocalyptic number.

It is an amenable number.

126551561 is a deficient number, since it is larger than the sum of its proper divisors (382663).

126551561 is an equidigital number, since it uses as much as digits as its factorization.

126551561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382662.

The product of its digits is 9000, while the sum is 32.

The square root of 126551561 is about 11249.5138117165. The cubic root of 126551561 is about 502.0602471038.

The spelling of 126551561 in words is "one hundred twenty-six million, five hundred fifty-one thousand, five hundred sixty-one".