1681537 has 12 divisors (see below), whose sum is σ = 1992340. Its totient is φ = 1409760.

The previous prime is 1681517. The next prime is 1681541. The reversal of 1681537 is 7351861.

It can be written as a sum of positive squares in 2 ways, for example, as 495616 + 1185921 = 704^2 + 1089^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1681537 is a prime.

It is a Duffinian number.

1681537 is a lucky number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 1681499 and 1681508.

It is not an unprimeable number, because it can be changed into a prime (1681517) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1039 + ... + 2107.

2^1681537 is an apocalyptic number.

It is an amenable number.

1681537 is a deficient number, since it is larger than the sum of its proper divisors (310803).

1681537 is a wasteful number, since it uses less digits than its factorization.

1681537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104 (or 1093 counting only the distinct ones).

The product of its digits is 5040, while the sum is 31.

The square root of 1681537 is about 1296.7409147551. The cubic root of 1681537 is about 118.9146812116.

The spelling of 1681537 in words is "one million, six hundred eighty-one thousand, five hundred thirty-seven".