20639830 has 8 divisors (see below), whose sum is σ = 37151712. Its totient is φ = 8255928.

The previous prime is 20639807. The next prime is 20639837. The reversal of 20639830 is 3893602.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 20639792 and 20639801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1031982 + ... + 1032001.

It is an arithmetic number, because the mean of its divisors is an integer number (4643964).

Almost surely, 2^20639830 is an apocalyptic number.

20639830 is a deficient number, since it is larger than the sum of its proper divisors (16511882).

20639830 is a wasteful number, since it uses less digits than its factorization.

20639830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2063990.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20639830 is about 4543.1079670199. The cubic root of 20639830 is about 274.3060409095.

The spelling of 20639830 in words is "twenty million, six hundred thirty-nine thousand, eight hundred thirty".