20365415661 has 4 divisors (see below), whose sum is σ = 27153887552. Its totient is φ = 13576943772.

The previous prime is 20365415657. The next prime is 20365415723. The reversal of 20365415661 is 16651456302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20365415661 - 2² = 20365415657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20365415641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3394235941 + ... + 3394235946.

It is an arithmetic number, because the mean of its divisors is an integer number (6788471888).

Almost surely, 2^20365415661 is an apocalyptic number.

It is an amenable number.

20365415661 is a deficient number, since it is larger than the sum of its proper divisors (6788471891).

20365415661 is an equidigital number, since it uses as much as digits as its factorization.

20365415661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6788471890.

The product of its (nonzero) digits is 129600, while the sum is 39.

The spelling of 20365415661 in words is "twenty billion, three hundred sixty-five million, four hundred fifteen thousand, six hundred sixty-one".