1266761657 has 4 divisors (see below), whose sum is σ = 1447727616. Its totient is φ = 1085795700.

The previous prime is 1266761651. The next prime is 1266761663. The reversal of 1266761657 is 7561676621.

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 an interprime number because it is at equal distance from previous prime (1266761651) and next prime (1266761663).

It is a cyclic number.

It is not a de Polignac number, because 1266761657 - 2¹⁴ = 1266745273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1266761651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90482969 + ... + 90482982.

It is an arithmetic number, because the mean of its divisors is an integer number (361931904).

Almost surely, 2^1266761657 is an apocalyptic number.

It is an amenable number.

1266761657 is a deficient number, since it is larger than the sum of its proper divisors (180965959).

1266761657 is an equidigital number, since it uses as much as digits as its factorization.

1266761657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180965958.

The product of its digits is 635040, while the sum is 47.

The square root of 1266761657 is about 35591.5953140626. The cubic root of 1266761657 is about 1082.0109016911.

The spelling of 1266761657 in words is "one billion, two hundred sixty-six million, seven hundred sixty-one thousand, six hundred fifty-seven".