21906336 has 96 divisors (see below), whose sum is σ = 62995968. Its totient is φ = 6635520.

The previous prime is 21906329. The next prime is 21906337. The reversal of 21906336 is 63360912.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (21906337) 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, 50376 + ... + 50808.

It is an arithmetic number, because the mean of its divisors is an integer number (656208).

Almost surely, 2^21906336 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 21906336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31497984).

21906336 is an abundant number, since it is smaller than the sum of its proper divisors (41089632).

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

21906336 is a wasteful number, since it uses less digits than its factorization.

21906336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494 (or 486 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 30.

The square root of 21906336 is about 4680.4204939300. The cubic root of 21906336 is about 279.8057155626.

The spelling of 21906336 in words is "twenty-one million, nine hundred six thousand, three hundred thirty-six".