20766617 has 4 divisors (see below), whose sum is σ = 20891136. Its totient is φ = 20642100.

The previous prime is 20766593. The next prime is 20766649. The reversal of 20766617 is 71666702.

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, and also an emirpimes, since its reverse is a distinct semiprime: 71666702 = 2 ⋅35833351.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20766617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20766817) 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, 62009 + ... + 62342.

It is an arithmetic number, because the mean of its divisors is an integer number (5222784).

Almost surely, 2^20766617 is an apocalyptic number.

It is an amenable number.

20766617 is a deficient number, since it is larger than the sum of its proper divisors (124519).

20766617 is a wasteful number, since it uses less digits than its factorization.

20766617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124518.

The product of its (nonzero) digits is 21168, while the sum is 35.

The square root of 20766617 is about 4557.0403772624. The cubic root of 20766617 is about 274.8665666720.

The spelling of 20766617 in words is "twenty million, seven hundred sixty-six thousand, six hundred seventeen".