20645716 has 36 divisors (see below), whose sum is σ = 44722272. Its totient is φ = 8165664.

The previous prime is 20645711. The next prime is 20645749. The reversal of 20645716 is 61754602.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2551 + ... + 6913.

Almost surely, 2^20645716 is an apocalyptic number.

20645716 is a gapful number since it is divisible by the number (26) 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 20645716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22361136).

20645716 is an abundant number, since it is smaller than the sum of its proper divisors (24076556).

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

20645716 is a wasteful number, since it uses less digits than its factorization.

20645716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4400 (or 4385 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 20645716 is about 4543.7557152646. The cubic root of 20645716 is about 274.3321136679.

The spelling of 20645716 in words is "twenty million, six hundred forty-five thousand, seven hundred sixteen".