20521839 has 24 divisors (see below), whose sum is σ = 31385232. Its totient is φ = 11880960.

The previous prime is 20521829. The next prime is 20521841. The reversal of 20521839 is 93812502.

It is a happy number.

It is not a de Polignac number, because 20521839 - 2⁵ = 20521807 is a prime.

It is a super-2 number, since 2×20521839² = 842291751883842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7429 + ... + 9809.

It is an arithmetic number, because the mean of its divisors is an integer number (1307718).

Almost surely, 2^20521839 is an apocalyptic number.

20521839 is a deficient number, since it is larger than the sum of its proper divisors (10863393).

20521839 is a wasteful number, since it uses less digits than its factorization.

20521839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2427 (or 2414 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 20521839 is about 4530.1036411985. The cubic root of 20521839 is about 273.7823364149.

The spelling of 20521839 in words is "twenty million, five hundred twenty-one thousand, eight hundred thirty-nine".