213727681 has 4 divisors (see below), whose sum is σ = 213837232. Its totient is φ = 213618132.

The previous prime is 213727649. The next prime is 213727691. The reversal of 213727681 is 186727312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 213727681 - 2⁵ = 213727649 is a prime.

It is a super-2 number, since 2×213727681² = 91359043251275522, which contains 22 as substring.

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 213727681.

It is not an unprimeable number, because it can be changed into a prime (213727691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51795 + ... + 55768.

It is an arithmetic number, because the mean of its divisors is an integer number (53459308).

Almost surely, 2^213727681 is an apocalyptic number.

It is an amenable number.

213727681 is a deficient number, since it is larger than the sum of its proper divisors (109551).

213727681 is a wasteful number, since it uses less digits than its factorization.

213727681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109550.

The product of its digits is 28224, while the sum is 37.

The square root of 213727681 is about 14619.4282035926. The cubic root of 213727681 is about 597.8885794806. Note that the first 3 decimals are identical.

The spelling of 213727681 in words is "two hundred thirteen million, seven hundred twenty-seven thousand, six hundred eighty-one".