20666111659 has 4 divisors (see below), whose sum is σ = 21881765304. Its totient is φ = 19450458016.

The previous prime is 20666111657. The next prime is 20666111671. The reversal of 20666111659 is 95611166602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20666111659 - 2¹ = 20666111657 is a prime.

It is a super-2 number, since 2×20666111659² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20666111657) 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, 607826797 + ... + 607826830.

It is an arithmetic number, because the mean of its divisors is an integer number (5470441326).

Almost surely, 2^20666111659 is an apocalyptic number.

20666111659 is a deficient number, since it is larger than the sum of its proper divisors (1215653645).

20666111659 is a wasteful number, since it uses less digits than its factorization.

20666111659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1215653644.

The product of its (nonzero) digits is 116640, while the sum is 43.

The spelling of 20666111659 in words is "twenty billion, six hundred sixty-six million, one hundred eleven thousand, six hundred fifty-nine".