20640238 has 8 divisors (see below), whose sum is σ = 31619232. Its totient is φ = 10100496.

The previous prime is 20640233. The next prime is 20640247. The reversal of 20640238 is 83204602.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20640233) 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, 109695 + ... + 109882.

It is an arithmetic number, because the mean of its divisors is an integer number (3952404).

Almost surely, 2^20640238 is an apocalyptic number.

20640238 is a deficient number, since it is larger than the sum of its proper divisors (10978994).

20640238 is a wasteful number, since it uses less digits than its factorization.

20640238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219626.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 20640238 is about 4543.1528699792. The cubic root of 20640238 is about 274.3078483554.

The spelling of 20640238 in words is "twenty million, six hundred forty thousand, two hundred thirty-eight".