21723798 has 24 divisors (see below), whose sum is σ = 44078328. Its totient is φ = 7137088.

The previous prime is 21723797. The next prime is 21723853. The reversal of 21723798 is 89732712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21723791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 121273 + ... + 121451.

It is an arithmetic number, because the mean of its divisors is an integer number (1836597).

Almost surely, 2^21723798 is an apocalyptic number.

21723798 is an abundant number, since it is smaller than the sum of its proper divisors (22354530).

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

21723798 is a wasteful number, since it uses less digits than its factorization.

21723798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 297 counting only the distinct ones).

The product of its digits is 42336, while the sum is 39.

The square root of 21723798 is about 4660.8795307324. The cubic root of 21723798 is about 279.0263717830.

The spelling of 21723798 in words is "twenty-one million, seven hundred twenty-three thousand, seven hundred ninety-eight".