21212364 has 12 divisors (see below), whose sum is σ = 49495544. Its totient is φ = 7070784.

The previous prime is 21212353. The next prime is 21212423. The reversal of 21212364 is 46321212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21212364.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883837 + ... + 883860.

Almost surely, 2^21212364 is an apocalyptic number.

It is an amenable number.

21212364 is an abundant number, since it is smaller than the sum of its proper divisors (28283180).

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

21212364 is a wasteful number, since it uses less digits than its factorization.

21212364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1767704 (or 1767702 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

The square root of 21212364 is about 4605.6882221879. The cubic root of 21212364 is about 276.8192941823.

Adding to 21212364 its reverse (46321212), we get a palindrome (67533576).

The spelling of 21212364 in words is "twenty-one million, two hundred twelve thousand, three hundred sixty-four".