20420264666 has 4 divisors (see below), whose sum is σ = 30630397002. Its totient is φ = 10210132332.

The previous prime is 20420264621. The next prime is 20420264707. The reversal of 20420264666 is 66646202402.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 11744273641 + 8675991025 = 108371^2 + 93145^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5105066165 + ... + 5105066168.

Almost surely, 2^20420264666 is an apocalyptic number.

20420264666 is a deficient number, since it is larger than the sum of its proper divisors (10210132336).

20420264666 is a wasteful number, since it uses less digits than its factorization.

20420264666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10210132335.

The product of its (nonzero) digits is 165888, while the sum is 38.

The spelling of 20420264666 in words is "twenty billion, four hundred twenty million, two hundred sixty-four thousand, six hundred sixty-six".