20006657 has 4 divisors (see below), whose sum is σ = 21825456. Its totient is φ = 18187860.

The previous prime is 20006641. The next prime is 20006663. The reversal of 20006657 is 75660002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20006657 - 2⁴ = 20006641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20006057) 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, 909383 + ... + 909404.

It is an arithmetic number, because the mean of its divisors is an integer number (5456364).

Almost surely, 2^20006657 is an apocalyptic number.

It is an amenable number.

20006657 is a deficient number, since it is larger than the sum of its proper divisors (1818799).

20006657 is a wasteful number, since it uses less digits than its factorization.

20006657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818798.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 20006657 is about 4472.8801683032. The cubic root of 20006657 is about 271.4718747821.

Adding to 20006657 its reverse (75660002), we get a palindrome (95666659).

The spelling of 20006657 in words is "twenty million, six thousand, six hundred fifty-seven".