21388798 has 16 divisors (see below), whose sum is σ = 33430320. Its totient is φ = 10254400.

The previous prime is 21388789. The next prime is 21388799. The reversal of 21388798 is 89788312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388799) 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, 2628 + ... + 7048.

It is an arithmetic number, because the mean of its divisors is an integer number (2089395).

Almost surely, 2^21388798 is an apocalyptic number.

21388798 is a deficient number, since it is larger than the sum of its proper divisors (12041522).

21388798 is a wasteful number, since it uses less digits than its factorization.

21388798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4523.

The product of its digits is 193536, while the sum is 46.

The square root of 21388798 is about 4624.8024822688. The cubic root of 21388798 is about 277.5846583138.

The spelling of 21388798 in words is "twenty-one million, three hundred eighty-eight thousand, seven hundred ninety-eight".