20205145 has 16 divisors (see below), whose sum is σ = 25102800. Its totient is φ = 15600384.

The previous prime is 20205139. The next prime is 20205193. The reversal of 20205145 is 54150202.

It can be written as a sum of positive squares in 8 ways, for example, as 1308736 + 18896409 = 1144^2 + 4347^2 .

It is not a de Polignac number, because 20205145 - 2⁹ = 20204633 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27199 + ... + 27931.

It is an arithmetic number, because the mean of its divisors is an integer number (1568925).

Almost surely, 2^20205145 is an apocalyptic number.

It is an amenable number.

20205145 is a deficient number, since it is larger than the sum of its proper divisors (4897655).

20205145 is a wasteful number, since it uses less digits than its factorization.

20205145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 924.

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

The square root of 20205145 is about 4495.0133481448. The cubic root of 20205145 is about 272.3666884326.

Adding to 20205145 its reverse (54150202), we get a palindrome (74355347).

The spelling of 20205145 in words is "twenty million, two hundred five thousand, one hundred forty-five".