102106311781 has 4 divisors (see below), whose sum is σ = 102111844492. Its totient is φ = 102100779072.

The previous prime is 102106311767. The next prime is 102106311821. The reversal of 102106311781 is 187113601201.

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: 187113601201 = 113 ⋅1655872577.

It can be written as a sum of positive squares in 2 ways, for example, as 76858690756 + 25247621025 = 277234^2 + 158895^2 .

It is a cyclic number.

It is not a de Polignac number, because 102106311781 - 2⁷ = 102106311653 is a prime.

It is a super-2 number, since 2×102106311781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102106311701) 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 in 3 ways as a sum of consecutive naturals, for example, 2738580 + ... + 2775613.

It is an arithmetic number, because the mean of its divisors is an integer number (25527961123).

Almost surely, 2^102106311781 is an apocalyptic number.

It is an amenable number.

102106311781 is a deficient number, since it is larger than the sum of its proper divisors (5532711).

102106311781 is an equidigital number, since it uses as much as digits as its factorization.

102106311781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5532710.

The product of its (nonzero) digits is 2016, while the sum is 31.

Adding to 102106311781 its reverse (187113601201), we get a palindrome (289219912982).

The spelling of 102106311781 in words is "one hundred two billion, one hundred six million, three hundred eleven thousand, seven hundred eighty-one".