1261923947 has 4 divisors (see below), whose sum is σ = 1261995120. Its totient is φ = 1261852776.

The previous prime is 1261923937. The next prime is 1261923989. The reversal of 1261923947 is 7493291621.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7493291621 = 22483 ⋅333287.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261923947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1261923898 and 1261923907.

It is not an unprimeable number, because it can be changed into a prime (1261923937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14633 + ... + 52325.

It is an arithmetic number, because the mean of its divisors is an integer number (315498780).

Almost surely, 2^1261923947 is an apocalyptic number.

1261923947 is a deficient number, since it is larger than the sum of its proper divisors (71173).

1261923947 is an equidigital number, since it uses as much as digits as its factorization.

1261923947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71172.

The product of its digits is 163296, while the sum is 44.

The square root of 1261923947 is about 35523.5688944678. The cubic root of 1261923947 is about 1080.6317597159.

The spelling of 1261923947 in words is "one billion, two hundred sixty-one million, nine hundred twenty-three thousand, nine hundred forty-seven".