1266161687 has 4 divisors (see below), whose sum is σ = 1447041936. Its totient is φ = 1085281440.

The previous prime is 1266161681. The next prime is 1266161711. The reversal of 1266161687 is 7861616621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7861616621 = 61 ⋅128878961.

It is a cyclic number.

It is not a de Polignac number, because 1266161687 - 2⁴ = 1266161671 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 (1266161681) 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, 90440114 + ... + 90440127.

It is an arithmetic number, because the mean of its divisors is an integer number (361760484).

Almost surely, 2^1266161687 is an apocalyptic number.

1266161687 is a deficient number, since it is larger than the sum of its proper divisors (180880249).

1266161687 is an equidigital number, since it uses as much as digits as its factorization.

1266161687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180880248.

The product of its digits is 145152, while the sum is 44.

The square root of 1266161687 is about 35583.1657810263. The cubic root of 1266161687 is about 1081.8400522414.

The spelling of 1266161687 in words is "one billion, two hundred sixty-six million, one hundred sixty-one thousand, six hundred eighty-seven".