21694320 has 120 divisors (see below), whose sum is σ = 75441600. Its totient is φ = 5580288.

The previous prime is 21694303. The next prime is 21694367. The reversal of 21694320 is 2349612.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is an unprimeable number.

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, 20361 + ... + 21399.

It is an arithmetic number, because the mean of its divisors is an integer number (628680).

Almost surely, 2^21694320 is an apocalyptic number.

21694320 is a gapful number since it is divisible by the number (20) 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 21694320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37720800).

21694320 is an abundant number, since it is smaller than the sum of its proper divisors (53747280).

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

21694320 is a wasteful number, since it uses less digits than its factorization.

21694320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1087 (or 1078 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21694320 is about 4657.7161785579. The cubic root of 21694320 is about 278.9001068369.

The spelling of 21694320 in words is "twenty-one million, six hundred ninety-four thousand, three hundred twenty".