210021220 has 24 divisors (see below), whose sum is σ = 442323000. Its totient is φ = 83764992.

The previous prime is 210021209. The next prime is 210021241. The reversal of 210021220 is 22120012.

It can be written as a sum of positive squares in 4 ways, for example, as 38044224 + 171976996 = 6168^2 + 13114^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 210021197 and 210021206.

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, 8065 + ... + 22024.

It is an arithmetic number, because the mean of its divisors is an integer number (18430125).

Almost surely, 2^210021220 is an apocalyptic number.

210021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

210021220 is an abundant number, since it is smaller than the sum of its proper divisors (232301780).

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

210021220 is a wasteful number, since it uses less digits than its factorization.

210021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30447 (or 30445 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 210021220 is about 14492.1088872531. The cubic root of 210021220 is about 594.4122152407.

Adding to 210021220 its reverse (22120012), we get a palindrome (232141232).

It can be divided in two parts, 21002 and 1220, that added together give a palindrome (22222).

The spelling of 210021220 in words is "two hundred ten million, twenty-one thousand, two hundred twenty".