20497521 has 12 divisors (see below), whose sum is σ = 30040976. Its totient is φ = 12422520.

The previous prime is 20497481. The next prime is 20497553. The reversal of 20497521 is 12579402.

It is not a de Polignac number, because 20497521 - 2¹¹ = 20495473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20497571) 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 11 ways as a sum of consecutive naturals, for example, 27871 + ... + 28596.

Almost surely, 2^20497521 is an apocalyptic number.

It is an amenable number.

20497521 is a deficient number, since it is larger than the sum of its proper divisors (9543455).

20497521 is a wasteful number, since it uses less digits than its factorization.

20497521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56492 (or 56481 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 20497521 is about 4527.4188010388. The cubic root of 20497521 is about 273.6741513347.

The spelling of 20497521 in words is "twenty million, four hundred ninety-seven thousand, five hundred twenty-one".