213836661 has 6 divisors (see below), whose sum is σ = 308875190. Its totient is φ = 142557768.

The previous prime is 213836641. The next prime is 213836683. The reversal of 213836661 is 166638312.

It can be written as a sum of positive squares in only one way, i.e., 190854225 + 22982436 = 13815^2 + 4794^2 .

It is not a de Polignac number, because 213836661 - 2⁵ = 213836629 is a prime.

It is a super-3 number, since 3×213836661³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213836641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11879806 + ... + 11879823.

Almost surely, 2^213836661 is an apocalyptic number.

It is an amenable number.

213836661 is a deficient number, since it is larger than the sum of its proper divisors (95038529).

213836661 is a wasteful number, since it uses less digits than its factorization.

213836661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23759635 (or 23759632 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 213836661 is about 14623.1549605412. The cubic root of 213836661 is about 597.9901835803.

The spelling of 213836661 in words is "two hundred thirteen million, eight hundred thirty-six thousand, six hundred sixty-one".