20185183661 has 2 divisors, whose sum is σ = 20185183662. Its totient is φ = 20185183660.

The previous prime is 20185183633. The next prime is 20185183687. The reversal of 20185183661 is 16638158102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11490553636 + 8694630025 = 107194^2 + 93245^2 .

It is a cyclic number.

It is not a de Polignac number, because 20185183661 - 2¹⁸ = 20184921517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20185183261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10092591830 + 10092591831.

It is an arithmetic number, because the mean of its divisors is an integer number (10092591831).

Almost surely, 2^20185183661 is an apocalyptic number.

It is an amenable number.

20185183661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20185183661 is an equidigital number, since it uses as much as digits as its factorization.

20185183661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69120, while the sum is 41.

The spelling of 20185183661 in words is "twenty billion, one hundred eighty-five million, one hundred eighty-three thousand, six hundred sixty-one".