1261111351 has 4 divisors (see below), whose sum is σ = 1273597704. Its totient is φ = 1248625000.

The previous prime is 1261111331. The next prime is 1261111373. The reversal of 1261111351 is 1531111621.

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

It is a cyclic number.

It is not a de Polignac number, because 1261111351 - 2²³ = 1252722743 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 (1261111331) 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, 6243025 + ... + 6243226.

It is an arithmetic number, because the mean of its divisors is an integer number (318399426).

Almost surely, 2^1261111351 is an apocalyptic number.

1261111351 is a deficient number, since it is larger than the sum of its proper divisors (12486353).

1261111351 is a wasteful number, since it uses less digits than its factorization.

1261111351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12486352.

The product of its digits is 180, while the sum is 22.

The square root of 1261111351 is about 35512.1296320004. The cubic root of 1261111351 is about 1080.3997579913.

Adding to 1261111351 its reverse (1531111621), we get a palindrome (2792222972).

The spelling of 1261111351 in words is "one billion, two hundred sixty-one million, one hundred eleven thousand, three hundred fifty-one".