20505538 has 4 divisors (see below), whose sum is σ = 30758310. Its totient is φ = 10252768.

The previous prime is 20505497. The next prime is 20505571. The reversal of 20505538 is 83550502.

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., 10975969 + 9529569 = 3313^2 + 3087^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5126383 + ... + 5126386.

Almost surely, 2^20505538 is an apocalyptic number.

20505538 is a deficient number, since it is larger than the sum of its proper divisors (10252772).

20505538 is a wasteful number, since it uses less digits than its factorization.

20505538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10252771.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 20505538 is about 4528.3040975624. The cubic root of 20505538 is about 273.7098265380.

The spelling of 20505538 in words is "twenty million, five hundred five thousand, five hundred thirty-eight".