21380394 has 32 divisors (see below), whose sum is σ = 49913856. Its totient is φ = 5978160.

The previous prime is 21380371. The next prime is 21380399. The reversal of 21380394 is 49308312.

It is not an unprimeable number, because it can be changed into a prime (21380399) 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, 3442 + ... + 7389.

It is an arithmetic number, because the mean of its divisors is an integer number (1559808).

Almost surely, 2^21380394 is an apocalyptic number.

21380394 is an abundant number, since it is smaller than the sum of its proper divisors (28533462).

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

21380394 is a wasteful number, since it uses less digits than its factorization.

21380394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10890.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 21380394 is about 4623.8938136597. The cubic root of 21380394 is about 277.5482977375.

The spelling of 21380394 in words is "twenty-one million, three hundred eighty thousand, three hundred ninety-four".