213423021 has 24 divisors (see below), whose sum is σ = 352961024. Its totient is φ = 121733280.

The previous prime is 213423017. The next prime is 213423037. The reversal of 213423021 is 120324312.

213423021 is a `hidden beast` number, since 21 + 342 + 302 + 1 = 666.

It is not a de Polignac number, because 213423021 - 2² = 213423017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213422985 and 213423003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213423071) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35451 + ... + 41031.

Almost surely, 2^213423021 is an apocalyptic number.

213423021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

213423021 is a deficient number, since it is larger than the sum of its proper divisors (139538003).

213423021 is a wasteful number, since it uses less digits than its factorization.

213423021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6201 (or 6198 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 213423021 is about 14609.0047915661. The cubic root of 213423021 is about 597.6043558792.

Adding to 213423021 its reverse (120324312), we get a palindrome (333747333).

The spelling of 213423021 in words is "two hundred thirteen million, four hundred twenty-three thousand, twenty-one".