20842521 has 16 divisors (see below), whose sum is σ = 31949184. Its totient is φ = 11839104.

The previous prime is 20842519. The next prime is 20842529. The reversal of 20842521 is 12524802.

It is not a de Polignac number, because 20842521 - 2¹ = 20842519 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20842491 and 20842500.

It is not an unprimeable number, because it can be changed into a prime (20842529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 765 + ... + 6501.

It is an arithmetic number, because the mean of its divisors is an integer number (1996824).

Almost surely, 2^20842521 is an apocalyptic number.

20842521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20842521 is a deficient number, since it is larger than the sum of its proper divisors (11106663).

20842521 is a wasteful number, since it uses less digits than its factorization.

20842521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5920.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 20842521 is about 4565.3609933936. The cubic root of 20842521 is about 275.2010474724.

The spelling of 20842521 in words is "twenty million, eight hundred forty-two thousand, five hundred twenty-one".