213687945 has 12 divisors (see below), whose sum is σ = 370392516. Its totient is φ = 113966880.

The previous prime is 213687931. The next prime is 213687953. The reversal of 213687945 is 549786312.

It can be written as a sum of positive squares in 2 ways, for example, as 101666889 + 112021056 = 10083^2 + 10584^2 .

It is not a de Polignac number, because 213687945 - 2¹¹ = 213685897 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 4748621 = 213687945 / (2 + 1 + 3 + 6 + 8 + 7 + 9 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 213687945.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2374266 + ... + 2374355.

It is an arithmetic number, because the mean of its divisors is an integer number (30866043).

Almost surely, 2^213687945 is an apocalyptic number.

It is an amenable number.

213687945 is a deficient number, since it is larger than the sum of its proper divisors (156704571).

213687945 is a wasteful number, since it uses less digits than its factorization.

213687945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4748632 (or 4748629 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 213687945 is about 14618.0691269401. The cubic root of 213687945 is about 597.8515242694.

The spelling of 213687945 in words is "two hundred thirteen million, six hundred eighty-seven thousand, nine hundred forty-five".