21445936 has 40 divisors (see below), whose sum is σ = 43863264. Its totient is φ = 10137600.

The previous prime is 21445933. The next prime is 21445943. The reversal of 21445936 is 63954412.

It is a happy number.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21445933) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36880 + ... + 37456.

Almost surely, 2^21445936 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 21445936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21931632).

21445936 is an abundant number, since it is smaller than the sum of its proper divisors (22417328).

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

21445936 is a wasteful number, since it uses less digits than its factorization.

21445936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709 (or 703 counting only the distinct ones).

The product of its digits is 25920, while the sum is 34.

The square root of 21445936 is about 4630.9757071270. The cubic root of 21445936 is about 277.8316182688.

The spelling of 21445936 in words is "twenty-one million, four hundred forty-five thousand, nine hundred thirty-six".