21012910 has 32 divisors (see below), whose sum is σ = 39517632. Its totient is φ = 8037120.

The previous prime is 21012889. The next prime is 21012913. The reversal of 21012910 is 1921012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21247 + ... + 22213.

It is an arithmetic number, because the mean of its divisors is an integer number (1234926).

Almost surely, 2^21012910 is an apocalyptic number.

21012910 is a deficient number, since it is larger than the sum of its proper divisors (18504722).

21012910 is a wasteful number, since it uses less digits than its factorization.

21012910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 21012910 is about 4583.9840750160. The cubic root of 21012910 is about 275.9489421061.

Adding to 21012910 its reverse (1921012), we get a palindrome (22933922).

The spelling of 21012910 in words is "twenty-one million, twelve thousand, nine hundred ten".