1261431371 has 4 divisors (see below), whose sum is σ = 1266227952. Its totient is φ = 1256634792.

The previous prime is 1261431361. The next prime is 1261431377. The reversal of 1261431371 is 1731341621.

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 1261431371 - 2³⁰ = 187689547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261431377) 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, 2397896 + ... + 2398421.

It is an arithmetic number, because the mean of its divisors is an integer number (316556988).

Almost surely, 2^1261431371 is an apocalyptic number.

1261431371 is a deficient number, since it is larger than the sum of its proper divisors (4796581).

1261431371 is an equidigital number, since it uses as much as digits as its factorization.

1261431371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4796580.

The product of its digits is 3024, while the sum is 29.

The square root of 1261431371 is about 35516.6351305976. The cubic root of 1261431371 is about 1080.4911377860.

Adding to 1261431371 its reverse (1731341621), we get a palindrome (2992772992).

The spelling of 1261431371 in words is "one billion, two hundred sixty-one million, four hundred thirty-one thousand, three hundred seventy-one".