20640738 has 8 divisors (see below), whose sum is σ = 41281488. Its totient is φ = 6880244.

The previous prime is 20640733. The next prime is 20640751. The reversal of 20640738 is 83704602.

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

20640738 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (20640733) 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, 1720056 + ... + 1720067.

It is an arithmetic number, because the mean of its divisors is an integer number (5160186).

Almost surely, 2^20640738 is an apocalyptic number.

20640738 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.

20640738 is a wasteful number, since it uses less digits than its factorization.

20640738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3440128.

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 20640738 is about 4543.2078975103. The cubic root of 20640738 is about 274.3100633301.

The spelling of 20640738 in words is "twenty million, six hundred forty thousand, seven hundred thirty-eight".