102731905 has 4 divisors (see below), whose sum is σ = 123278292. Its totient is φ = 82185520.

The previous prime is 102731897. The next prime is 102731927. The reversal of 102731905 is 509137201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 509137201 = 5113 ⋅99577.

It can be written as a sum of positive squares in 2 ways, for example, as 77158656 + 25573249 = 8784^2 + 5057^2 .

It is not a de Polignac number, because 102731905 - 2³ = 102731897 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10273186 + ... + 10273195.

It is an arithmetic number, because the mean of its divisors is an integer number (30819573).

Almost surely, 2^102731905 is an apocalyptic number.

It is an amenable number.

102731905 is a deficient number, since it is larger than the sum of its proper divisors (20546387).

102731905 is an equidigital number, since it uses as much as digits as its factorization.

102731905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20546386.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 102731905 is about 10135.6748665296. The cubic root of 102731905 is about 468.3477597016.

The spelling of 102731905 in words is "one hundred two million, seven hundred thirty-one thousand, nine hundred five".