1681370645 has 16 divisors (see below), whose sum is σ = 2050991280. Its totient is φ = 1323024384.

The previous prime is 1681370641. The next prime is 1681370693. The reversal of 1681370645 is 5460731861.

It can be written as a sum of positive squares in 8 ways, for example, as 14853316 + 1666517329 = 3854^2 + 40823^2 .

It is a cyclic number.

It is not a de Polignac number, because 1681370645 - 2² = 1681370641 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681370641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76097 + ... + 95673.

It is an arithmetic number, because the mean of its divisors is an integer number (128186955).

Almost surely, 2^1681370645 is an apocalyptic number.

It is an amenable number.

1681370645 is a deficient number, since it is larger than the sum of its proper divisors (369620635).

1681370645 is a wasteful number, since it uses less digits than its factorization.

1681370645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19864.

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 1681370645 is about 41004.5198118451. The cubic root of 1681370645 is about 1189.1075965964.

The spelling of 1681370645 in words is "one billion, six hundred eighty-one million, three hundred seventy thousand, six hundred forty-five".