20102661 has 12 divisors (see below), whose sum is σ = 30112992. Its totient is φ = 13401612.

The previous prime is 20102659. The next prime is 20102671. The reversal of 20102661 is 16620102.

It is a happy number.

20102661 is a `hidden beast` number, since 2 + 0 + 1 + 0 + 2 + 661 = 666.

It is not a de Polignac number, because 20102661 - 2¹ = 20102659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20102671) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41121 + ... + 41606.

It is an arithmetic number, because the mean of its divisors is an integer number (2509416).

Almost surely, 2^20102661 is an apocalyptic number.

It is an amenable number.

20102661 is a deficient number, since it is larger than the sum of its proper divisors (10010331).

20102661 is an frugal number, since it uses more digits than its factorization.

20102661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82742 (or 82730 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 20102661 is about 4483.5991123204. The cubic root of 20102661 is about 271.9054106292.

Adding to 20102661 its reverse (16620102), we get a palindrome (36722763).

The spelling of 20102661 in words is "twenty million, one hundred two thousand, six hundred sixty-one".