1261236431 has 24 divisors (see below), whose sum is σ = 1584100224. Its totient is φ = 995319360.

The previous prime is 1261236413. The next prime is 1261236437. The reversal of 1261236431 is 1346321621.

It is a de Polignac number, because none of the positive numbers 2^k-1261236431 is a prime.

It is a super-2 number, since 2×1261236431² = 3181434669763235522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1261236394 and 1261236403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261236437) 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 23 ways as a sum of consecutive naturals, for example, 265826 + ... + 270528.

It is an arithmetic number, because the mean of its divisors is an integer number (66004176).

Almost surely, 2^1261236431 is an apocalyptic number.

1261236431 is a deficient number, since it is larger than the sum of its proper divisors (322863793).

1261236431 is a wasteful number, since it uses less digits than its factorization.

1261236431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5151 (or 5144 counting only the distinct ones).

The product of its digits is 5184, while the sum is 29.

The square root of 1261236431 is about 35513.8906767479. The cubic root of 1261236431 is about 1080.4354756764.

The spelling of 1261236431 in words is "one billion, two hundred sixty-one million, two hundred thirty-six thousand, four hundred thirty-one".