20534639 has 4 divisors (see below), whose sum is σ = 21242760. Its totient is φ = 19826520.

The previous prime is 20534603. The next prime is 20534669. The reversal of 20534639 is 93643502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20534639 - 2²⁴ = 3757423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20534669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354017 + ... + 354074.

It is an arithmetic number, because the mean of its divisors is an integer number (5310690).

Almost surely, 2^20534639 is an apocalyptic number.

20534639 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

20534639 is a deficient number, since it is larger than the sum of its proper divisors (708121).

20534639 is an equidigital number, since it uses as much as digits as its factorization.

20534639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708120.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 20534639 is about 4531.5161921812. The cubic root of 20534639 is about 273.8392462848.

The spelling of 20534639 in words is "twenty million, five hundred thirty-four thousand, six hundred thirty-nine".