20992521 has 8 divisors (see below), whose sum is σ = 30534624. Its totient is φ = 12722720.

The previous prime is 20992513. The next prime is 20992523. The reversal of 20992521 is 12529902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20992521 - 2³ = 20992513 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20992523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 318036 + ... + 318101.

It is an arithmetic number, because the mean of its divisors is an integer number (3816828).

Almost surely, 2^20992521 is an apocalyptic number.

It is an amenable number.

20992521 is a deficient number, since it is larger than the sum of its proper divisors (9542103).

20992521 is a wasteful number, since it uses less digits than its factorization.

20992521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636151.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 20992521 is about 4581.7595964869. The cubic root of 20992521 is about 275.8596613779.

The spelling of 20992521 in words is "twenty million, nine hundred ninety-two thousand, five hundred twenty-one".