20390718667 has 4 divisors (see below), whose sum is σ = 22244420376. Its totient is φ = 18537016960.

The previous prime is 20390718529. The next prime is 20390718703. The reversal of 20390718667 is 76681709302.

It is a happy number.

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

It is not a de Polignac number, because 20390718667 - 2¹⁵ = 20390685899 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20390718667.

It is not an unprimeable number, because it can be changed into a prime (20390716667) 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, 926850838 + ... + 926850859.

It is an arithmetic number, because the mean of its divisors is an integer number (5561105094).

Almost surely, 2^20390718667 is an apocalyptic number.

20390718667 is a deficient number, since it is larger than the sum of its proper divisors (1853701709).

20390718667 is a wasteful number, since it uses less digits than its factorization.

20390718667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1853701708.

The product of its (nonzero) digits is 762048, while the sum is 49.

The spelling of 20390718667 in words is "twenty billion, three hundred ninety million, seven hundred eighteen thousand, six hundred sixty-seven".