20642816 has 44 divisors (see below), whose sum is σ = 43478280. Its totient is φ = 9768960.

The previous prime is 20642789. The next prime is 20642821. The reversal of 20642816 is 61824602.

It is a super-2 number, since 2×20642816² = 852251704819712, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 18926 + ... + 19986.

Almost surely, 2^20642816 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 20642816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21739140).

20642816 is an abundant number, since it is smaller than the sum of its proper divisors (22835464).

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

20642816 is a wasteful number, since it uses less digits than its factorization.

20642816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100 (or 1082 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 20642816 is about 4543.4365847891. The cubic root of 20642816 is about 274.3192683818.

The spelling of 20642816 in words is "twenty million, six hundred forty-two thousand, eight hundred sixteen".