20505051 has 12 divisors (see below), whose sum is σ = 33849712. Its totient is φ = 11717136.

The previous prime is 20505049. The next prime is 20505083. The reversal of 20505051 is 15050502.

It is not a de Polignac number, because 20505051 - 2¹ = 20505049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20505031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162676 + ... + 162801.

Almost surely, 2^20505051 is an apocalyptic number.

20505051 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20505051 is a deficient number, since it is larger than the sum of its proper divisors (13344661).

20505051 is a wasteful number, since it uses less digits than its factorization.

20505051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325490 (or 325487 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

The square root of 20505051 is about 4528.2503243527. The cubic root of 20505051 is about 273.7076596805.

Adding to 20505051 its reverse (15050502), we get a palindrome (35555553).

The spelling of 20505051 in words is "twenty million, five hundred five thousand, fifty-one".