20420145 has 24 divisors (see below), whose sum is σ = 37478376. Its totient is φ = 10249728.

The previous prime is 20420129. The next prime is 20420167. The reversal of 20420145 is 54102402.

It can be written as a sum of positive squares in 4 ways, for example, as 197136 + 20223009 = 444^2 + 4497^2 .

It is not a de Polignac number, because 20420145 - 2⁴ = 20420129 is a prime.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 12582 + ... + 14111.

It is an arithmetic number, because the mean of its divisors is an integer number (1561599).

Almost surely, 2^20420145 is an apocalyptic number.

It is an amenable number.

20420145 is a deficient number, since it is larger than the sum of its proper divisors (17058231).

20420145 is a wasteful number, since it uses less digits than its factorization.

20420145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26721 (or 26718 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 20420145 is about 4518.8654549566. The cubic root of 20420145 is about 273.3293533362.

Adding to 20420145 its reverse (54102402), we get a palindrome (74522547).

The spelling of 20420145 in words is "twenty million, four hundred twenty thousand, one hundred forty-five".