1821537 has 6 divisors (see below), whose sum is σ = 2631122. Its totient is φ = 1214352.

The previous prime is 1821509. The next prime is 1821541. The reversal of 1821537 is 7351281.

It can be written as a sum of positive squares in only one way, i.e., 1245456 + 576081 = 1116^2 + 759^2 .

It is not a de Polignac number, because 1821537 - 2⁷ = 1821409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1821537.

It is not an unprimeable number, because it can be changed into a prime (1821037) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 101188 + ... + 101205.

2^1821537 is an apocalyptic number.

It is an amenable number.

1821537 is a deficient number, since it is larger than the sum of its proper divisors (809585).

1821537 is a wasteful number, since it uses less digits than its factorization.

1821537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202399 (or 202396 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 1821537 is about 1349.6432862057. The cubic root of 1821537 is about 122.1272746834.

The spelling of 1821537 in words is "one million, eight hundred twenty-one thousand, five hundred thirty-seven".