1206811891 has 2 divisors, whose sum is σ = 1206811892. Its totient is φ = 1206811890.

The previous prime is 1206811883. The next prime is 1206811897. The reversal of 1206811891 is 1981186021.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1206811891 - 2³ = 1206811883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1206811891.

It is not a weakly prime, because it can be changed into another prime (1206811897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 603405945 + 603405946.

It is an arithmetic number, because the mean of its divisors is an integer number (603405946).

Almost surely, 2^1206811891 is an apocalyptic number.

1206811891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1206811891 is an equidigital number, since it uses as much as digits as its factorization.

1206811891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 37.

The square root of 1206811891 is about 34739.1981916682. The cubic root of 1206811891 is about 1064.6655303880.

The spelling of 1206811891 in words is "one billion, two hundred six million, eight hundred eleven thousand, eight hundred ninety-one".