1255721 has 2 divisors, whose sum is σ = 1255722. Its totient is φ = 1255720.

The previous prime is 1255693. The next prime is 1255747. The reversal of 1255721 is 1275521.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 714025 + 541696 = 845^2 + 736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1255721 is a prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (1255021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 627860 + 627861.

It is an arithmetic number, because the mean of its divisors is an integer number (627861).

2^1255721 is an apocalyptic number.

It is an amenable number.

1255721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1255721 is an equidigital number, since it uses as much as digits as its factorization.

1255721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 700, while the sum is 23.

The square root of 1255721 is about 1120.5895769638. The cubic root of 1255721 is about 107.8858246978.

The spelling of 1255721 in words is "one million, two hundred fifty-five thousand, seven hundred twenty-one".