126640815661 has 4 divisors (see below), whose sum is σ = 126801732352. Its totient is φ = 126479898972.

The previous prime is 126640815659. The next prime is 126640815671. The reversal of 126640815661 is 166518046621.

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 126640815661 - 2¹ = 126640815659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126640815601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80457165 + ... + 80458738.

It is an arithmetic number, because the mean of its divisors is an integer number (31700433088).

Almost surely, 2^126640815661 is an apocalyptic number.

It is an amenable number.

126640815661 is a deficient number, since it is larger than the sum of its proper divisors (160916691).

126640815661 is an equidigital number, since it uses as much as digits as its factorization.

126640815661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160916690.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 126640815661 in words is "one hundred twenty-six billion, six hundred forty million, eight hundred fifteen thousand, six hundred sixty-one".