20665623 has 16 divisors (see below), whose sum is σ = 31030272. Its totient is φ = 12120000.

The previous prime is 20665621. The next prime is 20665649. The reversal of 20665623 is 32656602.

It is not a de Polignac number, because 20665623 - 2¹ = 20665621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20665621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9078 + ... + 11123.

It is an arithmetic number, because the mean of its divisors is an integer number (1939392).

Almost surely, 2^20665623 is an apocalyptic number.

20665623 is a deficient number, since it is larger than the sum of its proper divisors (10364649).

20665623 is a wasteful number, since it uses less digits than its factorization.

20665623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20246.

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 20665623 is about 4545.9457761834. The cubic root of 20665623 is about 274.4202574598.

The spelling of 20665623 in words is "twenty million, six hundred sixty-five thousand, six hundred twenty-three".