20107115661 has 4 divisors (see below), whose sum is σ = 26809487552. Its totient is φ = 13404743772.

The previous prime is 20107115599. The next prime is 20107115671. The reversal of 20107115661 is 16651170102.

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 20107115661 - 2⁶ = 20107115597 is a prime.

It is a super-2 number, since 2×20107115661² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20107115671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3351185941 + ... + 3351185946.

It is an arithmetic number, because the mean of its divisors is an integer number (6702371888).

Almost surely, 2^20107115661 is an apocalyptic number.

It is an amenable number.

20107115661 is a deficient number, since it is larger than the sum of its proper divisors (6702371891).

20107115661 is an equidigital number, since it uses as much as digits as its factorization.

20107115661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6702371890.

The product of its (nonzero) digits is 2520, while the sum is 30.

Adding to 20107115661 its reverse (16651170102), we get a palindrome (36758285763).

The spelling of 20107115661 in words is "twenty billion, one hundred seven million, one hundred fifteen thousand, six hundred sixty-one".