21698928 has 60 divisors (see below), whose sum is σ = 62987288. Its totient is φ = 7231680.

The previous prime is 21698927. The next prime is 21698933. The reversal of 21698928 is 82989612.

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 (21698921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1098 + ... + 6678.

Almost surely, 2^21698928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21698928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31493644).

21698928 is an abundant number, since it is smaller than the sum of its proper divisors (41288360).

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

21698928 is an equidigital number, since it uses as much as digits as its factorization.

21698928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5604 (or 5586 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 21698928 is about 4658.2108153238. The cubic root of 21698928 is about 278.9198521083.

The spelling of 21698928 in words is "twenty-one million, six hundred ninety-eight thousand, nine hundred twenty-eight".