20420456 has 48 divisors (see below), whose sum is σ = 45031140. Its totient is φ = 8655360.

The previous prime is 20420453. The next prime is 20420479. The reversal of 20420456 is 65402402.

It can be written as a sum of positive squares in 2 ways, for example, as 17056900 + 3363556 = 4130^2 + 1834^2 .

It is not an unprimeable number, because it can be changed into a prime (20420453) 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, 44066 + ... + 44526.

Almost surely, 2^20420456 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 20420456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22515570).

20420456 is an abundant number, since it is smaller than the sum of its proper divisors (24610684).

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

20420456 is a wasteful number, since it uses less digits than its factorization.

20420456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20420456 is about 4518.8998661179. The cubic root of 20420456 is about 273.3307409365.

Adding to 20420456 its reverse (65402402), we get a palindrome (85822858).

The spelling of 20420456 in words is "twenty million, four hundred twenty thousand, four hundred fifty-six".