20528639 has 8 divisors (see below), whose sum is σ = 21999600. Its totient is φ = 19086976.

The previous prime is 20528623. The next prime is 20528647. The reversal of 20528639 is 93682502.

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 20528639 - 2⁴ = 20528623 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20528599 and 20528608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20528689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5864 + ... + 8685.

It is an arithmetic number, because the mean of its divisors is an integer number (2749950).

Almost surely, 2^20528639 is an apocalyptic number.

20528639 is a deficient number, since it is larger than the sum of its proper divisors (1470961).

20528639 is a wasteful number, since it uses less digits than its factorization.

20528639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14649.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 20528639 is about 4530.8541137406. The cubic root of 20528639 is about 273.8125727288.

The spelling of 20528639 in words is "twenty million, five hundred twenty-eight thousand, six hundred thirty-nine".