1995721 has 18 divisors (see below), whose sum is σ = 2524302. Its totient is φ = 1572480.

The previous prime is 1995713. The next prime is 1995727. The reversal of 1995721 is 1275991.

It can be written as a sum of positive squares in 3 ways, for example, as 35721 + 1960000 = 189^2 + 1400^2 .

It is not a de Polignac number, because 1995721 - 2³ = 1995713 is a prime.

It is a Duffinian number.

1995721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1995727) 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 17 ways as a sum of consecutive naturals, for example, 8161 + ... + 8401.

It is an arithmetic number, because the mean of its divisors is an integer number (140239).

2^1995721 is an apocalyptic number.

It is an amenable number.

1995721 is a deficient number, since it is larger than the sum of its proper divisors (528581).

1995721 is a wasteful number, since it uses less digits than its factorization.

1995721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281 (or 261 counting only the distinct ones).

The product of its digits is 5670, while the sum is 34.

The square root of 1995721 is about 1412.6998973597. The cubic root of 1995721 is about 125.9021874632.

The spelling of 1995721 in words is "one million, nine hundred ninety-five thousand, seven hundred twenty-one".