213021220 has 24 divisors (see below), whose sum is σ = 473659704. Its totient is φ = 80196096.

The previous prime is 213021191. The next prime is 213021223. The reversal of 213021220 is 22120312.

It can be written as a sum of positive squares in 4 ways, for example, as 11778624 + 201242596 = 3432^2 + 14186^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 213021220.

It is not an unprimeable number, because it can be changed into a prime (213021223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 312927 + ... + 313606.

It is an arithmetic number, because the mean of its divisors is an integer number (19735821).

Almost surely, 2^213021220 is an apocalyptic number.

213021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

213021220 is an abundant number, since it is smaller than the sum of its proper divisors (260638484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

213021220 is a wasteful number, since it uses less digits than its factorization.

213021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626559 (or 626557 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 213021220 is about 14595.2464864421. The cubic root of 213021220 is about 597.2290935315.

Adding to 213021220 its reverse (22120312), we get a palindrome (235141532).

It can be divided in two parts, 21302 and 1220, that added together give a palindrome (22522).

The spelling of 213021220 in words is "two hundred thirteen million, twenty-one thousand, two hundred twenty".