21318910 has 16 divisors (see below), whose sum is σ = 38427696. Its totient is φ = 8515648.

The previous prime is 21318889. The next prime is 21318911. The reversal of 21318910 is 1981312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11037 + ... + 12823.

It is an arithmetic number, because the mean of its divisors is an integer number (2401731).

Almost surely, 2^21318910 is an apocalyptic number.

21318910 is a deficient number, since it is larger than the sum of its proper divisors (17108786).

21318910 is a wasteful number, since it uses less digits than its factorization.

21318910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2987.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 21318910 is about 4617.2405178851. The cubic root of 21318910 is about 277.2819920190.

The spelling of 21318910 in words is "twenty-one million, three hundred eighteen thousand, nine hundred ten".