20451520 has 56 divisors (see below), whose sum is σ = 49377600. Its totient is φ = 8067072.

The previous prime is 20451517. The next prime is 20451521. The reversal of 20451520 is 2515402.

It is not an unprimeable number, because it can be changed into a prime (20451521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24876 + ... + 25684.

Almost surely, 2^20451520 is an apocalyptic number.

20451520 is a gapful number since it is divisible by the number (20) 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 20451520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24688800).

20451520 is an abundant number, since it is smaller than the sum of its proper divisors (28926080).

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

20451520 is an equidigital number, since it uses as much as digits as its factorization.

20451520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905 (or 895 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 20451520 is about 4522.3356797124. The cubic root of 20451520 is about 273.4692694189.

Adding to 20451520 its reverse (2515402), we get a palindrome (22966922).

The spelling of 20451520 in words is "twenty million, four hundred fifty-one thousand, five hundred twenty".