1125721 has 3 divisors (see below), whose sum is σ = 1126783.
Its totient is φ = 1124660.
The previous prime is 1125713. The next prime is 1125739. The reversal of 1125721 is 1275211.
The square root of 1125721 is 1061.
It is a perfect power (a square), and thus also a powerful number.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It can be written as a sum of positive squares in only one way, i.e., 741321 + 384400 = 861^2 + 620^2
It is not a de Polignac number, because 1125721 - 23 = 1125713 is a prime.
It is a Duffinian number.
1125721 is a lucky number.
It is not an unprimeable number, because it can be changed into a prime (1125701) by changing a digit.
It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 531 + ... + 1591.
21125721 is an apocalyptic number.
1125721 is the 1061-st square number.
1125721 is the 531-st centered octagonal number.
It is an amenable number.
1125721 is a deficient number, since it is larger than the sum of its proper divisors (1062).
1125721 is an frugal number, since it uses more digits than its factorization.
1125721 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2122 (or 1061 counting only the distinct ones).
The product of its digits is 140, while the sum is 19.
The cubic root of 1125721 is about 104.0264047846.
The spelling of 1125721 in words is "one million, one hundred twenty-five thousand, seven hundred twenty-one".