21838464 has 128 divisors (see below), whose sum is σ = 66096000. Its totient is φ = 7096320.

The previous prime is 21838457. The next prime is 21838469. The reversal of 21838464 is 46483812.

21838464 is a `hidden beast` number, since 218 + 384 + 64 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21838469) 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, 245332 + ... + 245420.

It is an arithmetic number, because the mean of its divisors is an integer number (516375).

Almost surely, 2^21838464 is an apocalyptic number.

21838464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21838464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33048000).

21838464 is an abundant number, since it is smaller than the sum of its proper divisors (44257536).

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

21838464 is an equidigital number, since it uses as much as digits as its factorization.

21838464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 165 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 21838464 is about 4673.1642385005. The cubic root of 21838464 is about 279.5164442990.

The spelling of 21838464 in words is "twenty-one million, eight hundred thirty-eight thousand, four hundred sixty-four".