21213652 has 12 divisors (see below), whose sum is σ = 39077920. Its totient is φ = 10048536.

The previous prime is 21213631. The next prime is 21213667. The reversal of 21213652 is 25631212.

It is a congruent number.

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, 139488 + ... + 139639.

Almost surely, 2^21213652 is an apocalyptic number.

It is an amenable number.

21213652 is a deficient number, since it is larger than the sum of its proper divisors (17864268).

21213652 is a wasteful number, since it uses less digits than its factorization.

21213652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279150 (or 279148 counting only the distinct ones).

The product of its digits is 720, while the sum is 22.

The square root of 21213652 is about 4605.8280471594. The cubic root of 21213652 is about 276.8248968273.

Adding to 21213652 its reverse (25631212), we get a palindrome (46844864).

The spelling of 21213652 in words is "twenty-one million, two hundred thirteen thousand, six hundred fifty-two".