213712021 has 16 divisors (see below), whose sum is σ = 229299840. Its totient is φ = 198696960.

The previous prime is 213712013. The next prime is 213712033. The reversal of 213712021 is 120217312.

It is a cyclic number.

It is not a de Polignac number, because 213712021 - 2³ = 213712013 is a prime.

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 213712021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213712621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 277525 + ... + 278293.

It is an arithmetic number, because the mean of its divisors is an integer number (14331240).

Almost surely, 2^213712021 is an apocalyptic number.

It is an amenable number.

213712021 is a deficient number, since it is larger than the sum of its proper divisors (15587819).

213712021 is a wasteful number, since it uses less digits than its factorization.

213712021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1116.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 213712021 is about 14618.8926051189. The cubic root of 213712021 is about 597.8739765307.

Adding to 213712021 its reverse (120217312), we get a palindrome (333929333).

The spelling of 213712021 in words is "two hundred thirteen million, seven hundred twelve thousand, twenty-one".