20451005 has 8 divisors (see below), whose sum is σ = 25140024. Its totient is φ = 15961600.

The previous prime is 20451001. The next prime is 20451007. The reversal of 20451005 is 50015402.

It can be written as a sum of positive squares in 4 ways, for example, as 755161 + 19695844 = 869^2 + 4438^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20451005 - 2² = 20451001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20451001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49676 + ... + 50085.

It is an arithmetic number, because the mean of its divisors is an integer number (3142503).

Almost surely, 2^20451005 is an apocalyptic number.

It is an amenable number.

20451005 is a deficient number, since it is larger than the sum of its proper divisors (4689019).

20451005 is an equidigital number, since it uses as much as digits as its factorization.

20451005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99807.

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 20451005 is about 4522.2787397506. The cubic root of 20451005 is about 273.4669739440.

Adding to 20451005 its reverse (50015402), we get a palindrome (70466407).

The spelling of 20451005 in words is "twenty million, four hundred fifty-one thousand, five".