20545505 has 4 divisors (see below), whose sum is σ = 24654612. Its totient is φ = 16436400.

The previous prime is 20545493. The next prime is 20545531. The reversal of 20545505 is 50554502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50554502 = 2 ⋅25277251.

It can be written as a sum of positive squares in 2 ways, for example, as 4800481 + 15745024 = 2191^2 + 3968^2 .

It is not a de Polignac number, because 20545505 - 2¹⁰ = 20544481 is a prime.

It is a Duffinian number.

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, 2054546 + ... + 2054555.

It is an arithmetic number, because the mean of its divisors is an integer number (6163653).

Almost surely, 2^20545505 is an apocalyptic number.

It is an amenable number.

20545505 is a deficient number, since it is larger than the sum of its proper divisors (4109107).

20545505 is an equidigital number, since it uses as much as digits as its factorization.

20545505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4109106.

The product of its (nonzero) digits is 5000, while the sum is 26.

The square root of 20545505 is about 4532.7149700814. The cubic root of 20545505 is about 273.8875388725.

The spelling of 20545505 in words is "twenty million, five hundred forty-five thousand, five hundred five".