213321021 has 16 divisors (see below), whose sum is σ = 304819584. Its totient is φ = 132352704.

The previous prime is 213321019. The next prime is 213321023. The reversal of 213321021 is 120123312.

It is an interprime number because it is at equal distance from previous prime (213321019) and next prime (213321023).

It is not a de Polignac number, because 213321021 - 2¹ = 213321019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213321023) 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, 39226 + ... + 44331.

It is an arithmetic number, because the mean of its divisors is an integer number (19051224).

Almost surely, 2^213321021 is an apocalyptic number.

It is an amenable number.

213321021 is a deficient number, since it is larger than the sum of its proper divisors (91498563).

213321021 is a wasteful number, since it uses less digits than its factorization.

213321021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83620.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 213321021 is about 14605.5133768040. The cubic root of 213321021 is about 597.5091375388.

Adding to 213321021 its reverse (120123312), we get a palindrome (333444333).

The spelling of 213321021 in words is "two hundred thirteen million, three hundred twenty-one thousand, twenty-one".