20420816 has 40 divisors (see below), whose sum is σ = 43997184. Its totient is φ = 9118080.

The previous prime is 20420773. The next prime is 20420821. The reversal of 20420816 is 61802402.

It is a super-2 number, since 2×20420816² = 834019452211712, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20420791 and 20420800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4865 + ... + 8031.

Almost surely, 2^20420816 is an apocalyptic number.

20420816 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 20420816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21998592).

20420816 is an abundant number, since it is smaller than the sum of its proper divisors (23576368).

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

20420816 is a wasteful number, since it uses less digits than its factorization.

20420816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3219 (or 3213 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 20420816 is about 4518.9396986461. The cubic root of 20420816 is about 273.3323471443.

The spelling of 20420816 in words is "twenty million, four hundred twenty thousand, eight hundred sixteen".