102009681 has 12 divisors (see below), whose sum is σ = 150941700. Its totient is φ = 66347520.

The previous prime is 102009679. The next prime is 102009709. The reversal of 102009681 is 186900201.

It can be written as a sum of positive squares in 2 ways, for example, as 13950225 + 88059456 = 3735^2 + 9384^2 .

It is not a de Polignac number, because 102009681 - 2¹ = 102009679 is a prime.

It is a super-2 number, since 2×102009681² = 20811950035443522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (102009601) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 137856 + ... + 138593.

It is an arithmetic number, because the mean of its divisors is an integer number (12578475).

Almost surely, 2^102009681 is an apocalyptic number.

It is an amenable number.

102009681 is a deficient number, since it is larger than the sum of its proper divisors (48932019).

102009681 is a wasteful number, since it uses less digits than its factorization.

102009681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276496 (or 276493 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 102009681 is about 10099.9842079084. The cubic root of 102009681 is about 467.2476543334.

Adding to 102009681 its reverse (186900201), we get a palindrome (288909882).

It can be divided in two parts, 10200 and 9681, that added together give a square (19881 = 141²).

The spelling of 102009681 in words is "one hundred two million, nine thousand, six hundred eighty-one".