20420545 has 4 divisors (see below), whose sum is σ = 24504660. Its totient is φ = 16336432.

The previous prime is 20420531. The next prime is 20420557. The reversal of 20420545 is 54502402.

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 13571856 + 6848689 = 3684^2 + 2617^2 .

It is a cyclic number.

It is not a de Polignac number, because 20420545 - 2⁹ = 20420033 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2042050 + ... + 2042059.

It is an arithmetic number, because the mean of its divisors is an integer number (6126165).

Almost surely, 2^20420545 is an apocalyptic number.

It is an amenable number.

20420545 is a deficient number, since it is larger than the sum of its proper divisors (4084115).

20420545 is an equidigital number, since it uses as much as digits as its factorization.

20420545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4084114.

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

The square root of 20420545 is about 4518.9097136367. The cubic root of 20420545 is about 273.3311380285.

Adding to 20420545 its reverse (54502402), we get a palindrome (74922947).

The spelling of 20420545 in words is "twenty million, four hundred twenty thousand, five hundred forty-five".