20639000 has 32 divisors (see below), whose sum is σ = 48297600. Its totient is φ = 8255200.

The previous prime is 20638973. The next prime is 20639009. The reversal of 20639000 is 93602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639009) 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 7 ways as a sum of consecutive naturals, for example, 9320 + ... + 11319.

It is an arithmetic number, because the mean of its divisors is an integer number (1509300).

Almost surely, 2^20639000 is an apocalyptic number.

20639000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20639000 is an abundant number, since it is smaller than the sum of its proper divisors (27658600).

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

20639000 is a wasteful number, since it uses less digits than its factorization.

20639000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20660 (or 20646 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

The square root of 20639000 is about 4543.0166189438. The cubic root of 20639000 is about 274.3023639240.

The spelling of 20639000 in words is "twenty million, six hundred thirty-nine thousand".