20172798208 has 18 divisors (see below), whose sum is σ = 40266796934. Its totient is φ = 10086398976.

The previous prime is 20172798203. The next prime is 20172798211. The reversal of 20172798208 is 80289727102.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17538234624 + 2634563584 = 132432^2 + 51328^2 .

It is a super-2 number, since 2×20172798208² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20172798203) by changing a digit.

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, 39399741 + ... + 39400252.

Almost surely, 2^20172798208 is an apocalyptic number.

It is an amenable number.

20172798208 is a deficient number, since it is larger than the sum of its proper divisors (20093998726).

20172798208 is an frugal number, since it uses more digits than its factorization.

20172798208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78800009 (or 78799995 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 46.

The spelling of 20172798208 in words is "twenty billion, one hundred seventy-two million, seven hundred ninety-eight thousand, two hundred eight".