1261331351 has 16 divisors (see below), whose sum is σ = 1450036224. Its totient is φ = 1074777984.

The previous prime is 1261331311. The next prime is 1261331389. The reversal of 1261331351 is 1531331621.

It is not a de Polignac number, because 1261331351 - 2¹⁸ = 1261069207 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261331351.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261331311) 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 15 ways as a sum of consecutive naturals, for example, 1186046 + ... + 1187108.

It is an arithmetic number, because the mean of its divisors is an integer number (90627264).

Almost surely, 2^1261331351 is an apocalyptic number.

1261331351 is a deficient number, since it is larger than the sum of its proper divisors (188704873).

1261331351 is a wasteful number, since it uses less digits than its factorization.

1261331351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910.

The product of its digits is 1620, while the sum is 26.

The square root of 1261331351 is about 35515.2270301064. The cubic root of 1261331351 is about 1080.4625793344.

Adding to 1261331351 its reverse (1531331621), we get a palindrome (2792662972).

The spelling of 1261331351 in words is "one billion, two hundred sixty-one million, three hundred thirty-one thousand, three hundred fifty-one".