1261240643 has 8 divisors (see below), whose sum is σ = 1360621248. Its totient is φ = 1162197504.

The previous prime is 1261240619. The next prime is 1261240649. The reversal of 1261240643 is 3460421621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1261240643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261240649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76571 + ... + 91572.

It is an arithmetic number, because the mean of its divisors is an integer number (170077656).

Almost surely, 2^1261240643 is an apocalyptic number.

1261240643 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1261240643 is a deficient number, since it is larger than the sum of its proper divisors (99380605).

1261240643 is a wasteful number, since it uses less digits than its factorization.

1261240643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168733.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 1261240643 is about 35513.9499774384. The cubic root of 1261240643 is about 1080.4366784086.

The spelling of 1261240643 in words is "one billion, two hundred sixty-one million, two hundred forty thousand, six hundred forty-three".