1225891 has 2 divisors, whose sum is σ = 1225892. Its totient is φ = 1225890.

The previous prime is 1225883. The next prime is 1225897. The reversal of 1225891 is 1985221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1225891 - 2³ = 1225883 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (1225897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 612945 + 612946.

It is an arithmetic number, because the mean of its divisors is an integer number (612946).

2^1225891 is an apocalyptic number.

1225891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1225891 is an equidigital number, since it uses as much as digits as its factorization.

1225891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 28.

The square root of 1225891 is about 1107.1996206647. The cubic root of 1225891 is about 107.0246835068.

It can be divided in two parts, 1225 and 891, that added together give a square (2116 = 46²).

The spelling of 1225891 in words is "one million, two hundred twenty-five thousand, eight hundred ninety-one".