20405146 has 4 divisors (see below), whose sum is σ = 30607722. Its totient is φ = 10202572.

The previous prime is 20405141. The next prime is 20405153. The reversal of 20405146 is 64150402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14100025 + 6305121 = 3755^2 + 2511^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20405141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5101285 + ... + 5101288.

Almost surely, 2^20405146 is an apocalyptic number.

20405146 is a deficient number, since it is larger than the sum of its proper divisors (10202576).

20405146 is a wasteful number, since it uses less digits than its factorization.

20405146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10202575.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 20405146 is about 4517.2055521085. The cubic root of 20405146 is about 273.2624150074.

Adding to 20405146 its reverse (64150402), we get a palindrome (84555548).

The spelling of 20405146 in words is "twenty million, four hundred five thousand, one hundred forty-six".