21440212 has 24 divisors (see below), whose sum is σ = 38666880. Its totient is φ = 10395840.

The previous prime is 21440207. The next prime is 21440233. The reversal of 21440212 is 21204412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38923 + ... + 39469.

It is an arithmetic number, because the mean of its divisors is an integer number (1611120).

Almost surely, 2^21440212 is an apocalyptic number.

It is an amenable number.

21440212 is a deficient number, since it is larger than the sum of its proper divisors (17226668).

21440212 is a wasteful number, since it uses less digits than its factorization.

21440212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831 (or 829 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21440212 is about 4630.3576535728. The cubic root of 21440212 is about 277.8068979723.

Adding to 21440212 its reverse (21204412), we get a palindrome (42644624).

The spelling of 21440212 in words is "twenty-one million, four hundred forty thousand, two hundred twelve".