1131721 has 2 divisors, whose sum is σ = 1131722. Its totient is φ = 1131720.

The previous prime is 1131701. The next prime is 1131727. The reversal of 1131721 is 1271311.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 881721 + 250000 = 939^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 1131721 - 2¹⁵ = 1098953 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1131695 and 1131704.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1131727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 565860 + 565861.

It is an arithmetic number, because the mean of its divisors is an integer number (565861).

2^1131721 is an apocalyptic number.

It is an amenable number.

1131721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1131721 is an equidigital number, since it uses as much as digits as its factorization.

1131721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42, while the sum is 16.

The square root of 1131721 is about 1063.8237636000. The cubic root of 1131721 is about 104.2108947830.

The spelling of 1131721 in words is "one million, one hundred thirty-one thousand, seven hundred twenty-one".