213121320 has 32 divisors (see below), whose sum is σ = 639364320. Its totient is φ = 56832320.

The previous prime is 213121313. The next prime is 213121343. The reversal of 213121320 is 23121312.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 213121320.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 887886 + ... + 888125.

It is an arithmetic number, because the mean of its divisors is an integer number (19980135).

Almost surely, 2^213121320 is an apocalyptic number.

213121320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

213121320 is an abundant number, since it is smaller than the sum of its proper divisors (426243000).

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

213121320 is a wasteful number, since it uses less digits than its factorization.

213121320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776025 (or 1776021 counting only the distinct ones).

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

The square root of 213121320 is about 14598.6752823672. The cubic root of 213121320 is about 597.3226261079.

Adding to 213121320 its reverse (23121312), we get a palindrome (236242632).

The spelling of 213121320 in words is "two hundred thirteen million, one hundred twenty-one thousand, three hundred twenty".