213031021 has 16 divisors (see below), whose sum is σ = 258255360. Its totient is φ = 171653040.

The previous prime is 213031019. The next prime is 213031031. The reversal of 213031021 is 120130312.

213031021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 213031021 - 2¹ = 213031019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213030992 and 213031010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213031001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11310 + ... + 23536.

It is an arithmetic number, because the mean of its divisors is an integer number (16140960).

Almost surely, 2^213031021 is an apocalyptic number.

It is an amenable number.

213031021 is a deficient number, since it is larger than the sum of its proper divisors (45224339).

213031021 is a wasteful number, since it uses less digits than its factorization.

213031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12384.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 213031021 is about 14595.5822425829. The cubic root of 213031021 is about 597.2382527952.

Adding to 213031021 its reverse (120130312), we get a palindrome (333161333).

The spelling of 213031021 in words is "two hundred thirteen million, thirty-one thousand, twenty-one".