1266726157 has 4 divisors (see below), whose sum is σ = 1270033920. Its totient is φ = 1263418396.

The previous prime is 1266726137. The next prime is 1266726179. The reversal of 1266726157 is 7516276621.

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 1266726157 - 2¹⁹ = 1266201869 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 (1266726137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1653307 + ... + 1654072.

It is an arithmetic number, because the mean of its divisors is an integer number (317508480).

Almost surely, 2^1266726157 is an apocalyptic number.

It is an amenable number.

1266726157 is a deficient number, since it is larger than the sum of its proper divisors (3307763).

1266726157 is an equidigital number, since it uses as much as digits as its factorization.

1266726157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3307762.

The product of its digits is 211680, while the sum is 43.

The square root of 1266726157 is about 35591.0965973233. The cubic root of 1266726157 is about 1082.0007940949. Note that the first 3 decimals are identical.

The spelling of 1266726157 in words is "one billion, two hundred sixty-six million, seven hundred twenty-six thousand, one hundred fifty-seven".