21212710 has 8 divisors (see below), whose sum is σ = 38182896. Its totient is φ = 8485080.

The previous prime is 21212701. The next prime is 21212731. The reversal of 21212710 is 1721212.

It is a sphenic number, since it is the product of 3 distinct primes.

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, 1060626 + ... + 1060645.

It is an arithmetic number, because the mean of its divisors is an integer number (4772862).

Almost surely, 2^21212710 is an apocalyptic number.

21212710 is a deficient number, since it is larger than the sum of its proper divisors (16970186).

21212710 is a wasteful number, since it uses less digits than its factorization.

21212710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121278.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21212710 is about 4605.7257842820. The cubic root of 21212710 is about 276.8207992629.

Adding to 21212710 its reverse (1721212), we get a palindrome (22933922).

The spelling of 21212710 in words is "twenty-one million, two hundred twelve thousand, seven hundred ten".