1681594605 has 18 divisors (see below), whose sum is σ = 2915240874. Its totient is φ = 896703744.

The previous prime is 1681594567. The next prime is 1681594631. The reversal of 1681594605 is 5064951861.

1681594605 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 225180036 + 1456414569 = 15006^2 + 38163^2 .

It is not a de Polignac number, because 1681594605 - 2¹¹ = 1681592557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 272029 + ... + 278141.

Almost surely, 2^1681594605 is an apocalyptic number.

1681594605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1681594605 is a deficient number, since it is larger than the sum of its proper divisors (1233646269).

1681594605 is an frugal number, since it uses more digits than its factorization.

1681594605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12237 (or 6121 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The square root of 1681594605 is about 41007.2506393686. The cubic root of 1681594605 is about 1189.1603909668.

Multiplying 1681594605 by its sum of digits (45), we get a square (75671757225 = 275085²).

1681594605 divided by its sum of digits (45) gives a square (37368769 = 6113²).

The spelling of 1681594605 in words is "one billion, six hundred eighty-one million, five hundred ninety-four thousand, six hundred five".