102005661 has 16 divisors (see below), whose sum is σ = 151588800. Its totient is φ = 60634368.

The previous prime is 102005653. The next prime is 102005671. The reversal of 102005661 is 166500201.

It is a happy number.

It is not a de Polignac number, because 102005661 - 2³ = 102005653 is a prime.

102005661 is a modest number, since divided by 5661 gives 102 as remainder.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102005611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51666 + ... + 53603.

It is an arithmetic number, because the mean of its divisors is an integer number (9474300).

Almost surely, 2^102005661 is an apocalyptic number.

It is an amenable number.

102005661 is a deficient number, since it is larger than the sum of its proper divisors (49583139).

102005661 is a wasteful number, since it uses less digits than its factorization.

102005661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105308.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 102005661 is about 10099.7851957356. The cubic root of 102005661 is about 467.2415164838.

Adding to 102005661 its reverse (166500201), we get a palindrome (268505862).

The spelling of 102005661 in words is "one hundred two million, five thousand, six hundred sixty-one".