20639994 has 8 divisors (see below), whose sum is σ = 41280000. Its totient is φ = 6879996.

The previous prime is 20639959. The next prime is 20640001. The reversal of 20639994 is 49993602.

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

20639994 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1719994 + ... + 1720005.

It is an arithmetic number, because the mean of its divisors is an integer number (5160000).

Almost surely, 2^20639994 is an apocalyptic number.

20639994 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20639994 is a wasteful number, since it uses less digits than its factorization.

20639994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3440004.

The product of its (nonzero) digits is 104976, while the sum is 42.

The square root of 20639994 is about 4543.1260163020. The cubic root of 20639994 is about 274.3067674347.

The spelling of 20639994 in words is "twenty million, six hundred thirty-nine thousand, nine hundred ninety-four".