20402545 has 4 divisors (see below), whose sum is σ = 24483060. Its totient is φ = 16322032.

The previous prime is 20402537. The next prime is 20402563. The reversal of 20402545 is 54520402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13198689 + 7203856 = 3633^2 + 2684^2 .

It is a cyclic number.

It is not a de Polignac number, because 20402545 - 2³ = 20402537 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 3 ways as a sum of consecutive naturals, for example, 2040250 + ... + 2040259.

It is an arithmetic number, because the mean of its divisors is an integer number (6120765).

Almost surely, 2^20402545 is an apocalyptic number.

It is an amenable number.

20402545 is a deficient number, since it is larger than the sum of its proper divisors (4080515).

20402545 is an equidigital number, since it uses as much as digits as its factorization.

20402545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4080514.

The product of its (nonzero) digits is 1600, while the sum is 22.

The square root of 20402545 is about 4516.9176437035. The cubic root of 20402545 is about 273.2508037902.

Adding to 20402545 its reverse (54520402), we get a palindrome (74922947).

The spelling of 20402545 in words is "twenty million, four hundred two thousand, five hundred forty-five".