20123120688661 has 4 divisors (see below), whose sum is σ = 20123379474912. Its totient is φ = 20122861902412.

The previous prime is 20123120688641. The next prime is 20123120688683. The reversal of 20123120688661 is 16688602132102.

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 a cyclic number.

It is not a de Polignac number, because 20123120688661 - 2²¹ = 20123118591509 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 (20123120688641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129276451 + ... + 129432016.

It is an arithmetic number, because the mean of its divisors is an integer number (5030844868728).

Almost surely, 2^{20123120688661} is an apocalyptic number.

It is an amenable number.

20123120688661 is a deficient number, since it is larger than the sum of its proper divisors (258786251).

20123120688661 is an equidigital number, since it uses as much as digits as its factorization.

20123120688661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258786250.

The product of its (nonzero) digits is 331776, while the sum is 46.

The spelling of 20123120688661 in words is "twenty trillion, one hundred twenty-three billion, one hundred twenty million, six hundred eighty-eight thousand, six hundred sixty-one".