21010212 has 48 divisors (see below), whose sum is σ = 54774720. Its totient is φ = 6964416.

The previous prime is 21010193. The next prime is 21010217. The reversal of 21010212 is 21201012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21010194 and 21010203.

It is not an unprimeable number, because it can be changed into a prime (21010217) 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, 24088 + ... + 24944.

It is an arithmetic number, because the mean of its divisors is an integer number (1141140).

Almost surely, 2^21010212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21010212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27387360).

21010212 is an abundant number, since it is smaller than the sum of its proper divisors (33764508).

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

21010212 is a wasteful number, since it uses less digits than its factorization.

21010212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1097 (or 1089 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21010212 is about 4583.6897800789. The cubic root of 21010212 is about 275.9371312382.

Adding to 21010212 its reverse (21201012), we get a palindrome (42211224).

The spelling of 21010212 in words is "twenty-one million, ten thousand, two hundred twelve".