1291950861 has 16 divisors (see below), whose sum is σ = 1770814080. Its totient is φ = 837527040.

The previous prime is 1291950851. The next prime is 1291950889. The reversal of 1291950861 is 1680591921.

It is not a de Polignac number, because 1291950861 - 2⁶ = 1291950797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291950851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25996 + ... + 57093.

It is an arithmetic number, because the mean of its divisors is an integer number (110675880).

Almost surely, 2^1291950861 is an apocalyptic number.

It is an amenable number.

1291950861 is a deficient number, since it is larger than the sum of its proper divisors (478863219).

1291950861 is an equidigital number, since it uses as much as digits as its factorization.

1291950861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83236.

The product of its (nonzero) digits is 38880, while the sum is 42.

The square root of 1291950861 is about 35943.7179629487. The cubic root of 1291950861 is about 1089.1357121951.

The spelling of 1291950861 in words is "one billion, two hundred ninety-one million, nine hundred fifty thousand, eight hundred sixty-one".