20078972666 has 4 divisors (see below), whose sum is σ = 30118459002. Its totient is φ = 10039486332.

The previous prime is 20078972659. The next prime is 20078972671. The reversal of 20078972666 is 66627987002.

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., 10083172225 + 9995800441 = 100415^2 + 99979^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5019743165 + ... + 5019743168.

Almost surely, 2^20078972666 is an apocalyptic number.

20078972666 is a deficient number, since it is larger than the sum of its proper divisors (10039486336).

20078972666 is a wasteful number, since it uses less digits than its factorization.

20078972666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10039486335.

The product of its (nonzero) digits is 3048192, while the sum is 53.

The spelling of 20078972666 in words is "twenty billion, seventy-eight million, nine hundred seventy-two thousand, six hundred sixty-six".