1525721 has 4 divisors (see below), whose sum is σ = 1530852. Its totient is φ = 1520592.

The previous prime is 1525717. The next prime is 1525723. The reversal of 1525721 is 1275251.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 547600 + 978121 = 740^2 + 989^2 .

It is a cyclic number.

It is not a de Polignac number, because 1525721 - 2² = 1525717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1525723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2090 + ... + 2723.

It is an arithmetic number, because the mean of its divisors is an integer number (382713).

2^1525721 is an apocalyptic number.

It is an amenable number.

1525721 is a deficient number, since it is larger than the sum of its proper divisors (5131).

1525721 is an equidigital number, since it uses as much as digits as its factorization.

1525721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5130.

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

The square root of 1525721 is about 1235.2007933935. The cubic root of 1525721 is about 115.1220129078.

The spelling of 1525721 in words is "one million, five hundred twenty-five thousand, seven hundred twenty-one".