21380910 has 16 divisors (see below), whose sum is σ = 51314256. Its totient is φ = 5701568.

The previous prime is 21380893. The next prime is 21380921. The reversal of 21380910 is 1908312.

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, 356319 + ... + 356378.

It is an arithmetic number, because the mean of its divisors is an integer number (3207141).

Almost surely, 2^21380910 is an apocalyptic number.

21380910 is an abundant number, since it is smaller than the sum of its proper divisors (29933346).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21380910 is a wasteful number, since it uses less digits than its factorization.

21380910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712707.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21380910 is about 4623.9496104521. The cubic root of 21380910 is about 277.5505305272.

The spelling of 21380910 in words is "twenty-one million, three hundred eighty thousand, nine hundred ten".