1156721 has 2 divisors, whose sum is σ = 1156722. Its totient is φ = 1156720.

The previous prime is 1156711. The next prime is 1156741. The reversal of 1156721 is 1276511.

1156721 = 760² + 761².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 579121 + 577600 = 761^2 + 760^2 .

It is an emirp because it is prime and its reverse (1276511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1156721 - 2¹⁰ = 1155697 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1156711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 578360 + 578361.

It is an arithmetic number, because the mean of its divisors is an integer number (578361).

2^1156721 is an apocalyptic number.

1156721 is the 761-st centered square number.

It is an amenable number.

1156721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1156721 is an equidigital number, since it uses as much as digits as its factorization.

1156721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 420, while the sum is 23.

The square root of 1156721 is about 1075.5096466327. The cubic root of 1156721 is about 104.9726610607.

The spelling of 1156721 in words is "one million, one hundred fifty-six thousand, seven hundred twenty-one".