21699396 has 72 divisors (see below), whose sum is σ = 58181760. Its totient is φ = 6804864.

The previous prime is 21699371. The next prime is 21699397. The reversal of 21699396 is 69399612.

It is a happy number.

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 (21699397) 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 23 ways as a sum of consecutive naturals, for example, 60265 + ... + 60623.

It is an arithmetic number, because the mean of its divisors is an integer number (808080).

Almost surely, 2^21699396 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 21699396, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29090880).

21699396 is an abundant number, since it is smaller than the sum of its proper divisors (36482364).

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

21699396 is a wasteful number, since it uses less digits than its factorization.

21699396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465 (or 460 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 21699396 is about 4658.2610489323. The cubic root of 21699396 is about 278.9218573311.

The spelling of 21699396 in words is "twenty-one million, six hundred ninety-nine thousand, three hundred ninety-six".