20518497 has 24 divisors (see below), whose sum is σ = 30820608. Its totient is φ = 13140000.

The previous prime is 20518493. The next prime is 20518523. The reversal of 20518497 is 79481502.

It is not a de Polignac number, because 20518497 - 2² = 20518493 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20518493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69883 + ... + 70175.

It is an arithmetic number, because the mean of its divisors is an integer number (1284192).

Almost surely, 2^20518497 is an apocalyptic number.

It is an amenable number.

20518497 is a deficient number, since it is larger than the sum of its proper divisors (10302111).

20518497 is a wasteful number, since it uses less digits than its factorization.

20518497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581 (or 578 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 20518497 is about 4529.7347604468. The cubic root of 20518497 is about 273.7674737079.

Adding to 20518497 its reverse (79481502), we get a palindrome (99999999).

The spelling of 20518497 in words is "twenty million, five hundred eighteen thousand, four hundred ninety-seven".