213636021 has 4 divisors (see below), whose sum is σ = 284848032. Its totient is φ = 142424012.

The previous prime is 213635921. The next prime is 213636037. The reversal of 213636021 is 120636312.

It is a happy number.

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 213636021 - 2⁷ = 213635893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213635982 and 213636000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213636721) 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, 35606001 + ... + 35606006.

It is an arithmetic number, because the mean of its divisors is an integer number (71212008).

Almost surely, 2^213636021 is an apocalyptic number.

It is an amenable number.

213636021 is a deficient number, since it is larger than the sum of its proper divisors (71212011).

213636021 is an equidigital number, since it uses as much as digits as its factorization.

213636021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71212010.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 213636021 is about 14616.2929978842. The cubic root of 213636021 is about 597.8030963975.

The spelling of 213636021 in words is "two hundred thirteen million, six hundred thirty-six thousand, twenty-one".