1261376478157 has 4 divisors (see below), whose sum is σ = 1261382591196. Its totient is φ = 1261370365120.

The previous prime is 1261376478151. The next prime is 1261376478161. The reversal of 1261376478157 is 7518746731621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 332599037796 + 928777440361 = 576714^2 + 963731^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261376478157 - 2²³ = 1261368089549 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261376478151) 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, 2735788 + ... + 3163429.

It is an arithmetic number, because the mean of its divisors is an integer number (315345647799).

Almost surely, 2^{1261376478157} is an apocalyptic number.

It is an amenable number.

1261376478157 is a deficient number, since it is larger than the sum of its proper divisors (6113039).

1261376478157 is an equidigital number, since it uses as much as digits as its factorization.

1261376478157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6113038.

The product of its digits is 11854080, while the sum is 58.

The spelling of 1261376478157 in words is "one trillion, two hundred sixty-one billion, three hundred seventy-six million, four hundred seventy-eight thousand, one hundred fifty-seven".