21370212 has 72 divisors (see below), whose sum is σ = 57512000. Its totient is φ = 6671808.

The previous prime is 21370199. The next prime is 21370249. The reversal of 21370212 is 21207312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107289 + ... + 107487.

Almost surely, 2^21370212 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 21370212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28756000).

21370212 is an abundant number, since it is smaller than the sum of its proper divisors (36141788).

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

21370212 is a wasteful number, since it uses less digits than its factorization.

21370212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 380 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21370212 is about 4622.7926624498. The cubic root of 21370212 is about 277.5042317348.

Adding to 21370212 its reverse (21207312), we get a palindrome (42577524).

The spelling of 21370212 in words is "twenty-one million, three hundred seventy thousand, two hundred twelve".