21556704 has 96 divisors (see below), whose sum is σ = 63673344. Its totient is φ = 6336000.

The previous prime is 21556699. The next prime is 21556709. The reversal of 21556704 is 40765512.

It is an interprime number because it is at equal distance from previous prime (21556699) and next prime (21556709).

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556709) 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, 28329 + ... + 29079.

It is an arithmetic number, because the mean of its divisors is an integer number (663264).

Almost surely, 2^21556704 is an apocalyptic number.

21556704 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 21556704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31836672).

21556704 is an abundant number, since it is smaller than the sum of its proper divisors (42116640).

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

21556704 is a wasteful number, since it uses less digits than its factorization.

21556704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800 (or 792 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 21556704 is about 4642.9197710062. The cubic root of 21556704 is about 278.3091294127.

The spelling of 21556704 in words is "twenty-one million, five hundred fifty-six thousand, seven hundred four".