212121020 has 24 divisors (see below), whose sum is σ = 451731168. Its totient is φ = 83652800.

The previous prime is 212120983. The next prime is 212121023. The reversal of 212121020 is 20121212.

It is a happy number.

It is a super-3 number, since 3×212121020³ (a number of 26 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 212120992 and 212121010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121023) 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, 73271 + ... + 76110.

It is an arithmetic number, because the mean of its divisors is an integer number (18822132).

Almost surely, 2^212121020 is an apocalyptic number.

212121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

212121020 is an abundant number, since it is smaller than the sum of its proper divisors (239610148).

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

212121020 is a wasteful number, since it uses less digits than its factorization.

212121020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149461 (or 149459 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 212121020 is about 14564.3750295026. The cubic root of 212121020 is about 596.3866348553.

Adding to 212121020 its reverse (20121212), we get a palindrome (232242232).

The spelling of 212121020 in words is "two hundred twelve million, one hundred twenty-one thousand, twenty".