20521589 has 16 divisors (see below), whose sum is σ = 24174720. Its totient is φ = 17223360.

The previous prime is 20521583. The next prime is 20521603. The reversal of 20521589 is 98512502.

It is not a de Polignac number, because 20521589 - 2⁴ = 20521573 is a prime.

It is a super-2 number, since 2×20521589² = 842271230169842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521583) 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, 5939 + ... + 8735.

It is an arithmetic number, because the mean of its divisors is an integer number (1510920).

Almost surely, 2^20521589 is an apocalyptic number.

20521589 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20521589 is a deficient number, since it is larger than the sum of its proper divisors (3653131).

20521589 is a wasteful number, since it uses less digits than its factorization.

20521589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2860.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 20521589 is about 4530.0760479268. The cubic root of 20521589 is about 273.7812246584.

Adding to 20521589 its sum of digits (32), we get a triangular number (20521621 = T₆₄₀₆).

The spelling of 20521589 in words is "twenty million, five hundred twenty-one thousand, five hundred eighty-nine".