102815817826 has 4 divisors (see below), whose sum is σ = 154223726742. Its totient is φ = 51407908912.

The previous prime is 102815817821. The next prime is 102815817857. The reversal of 102815817826 is 628718518201.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 628718518201 = 35573 ⋅17674037.

It can be written as a sum of positive squares in only one way, i.e., 101983783801 + 832034025 = 319349^2 + 28845^2 .

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 self number, because there is not a number n which added to its sum of digits gives 102815817826.

It is not an unprimeable number, because it can be changed into a prime (102815817821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25703954455 + ... + 25703954458.

Almost surely, 2^102815817826 is an apocalyptic number.

102815817826 is a deficient number, since it is larger than the sum of its proper divisors (51407908916).

102815817826 is an equidigital number, since it uses as much as digits as its factorization.

102815817826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51407908915.

The product of its (nonzero) digits is 430080, while the sum is 49.

The spelling of 102815817826 in words is "one hundred two billion, eight hundred fifteen million, eight hundred seventeen thousand, eight hundred twenty-six".