2129398659961 has 4 divisors (see below), whose sum is σ = 2158568504692. Its totient is φ = 2100228815232.

The previous prime is 2129398659953. The next prime is 2129398660027. The reversal of 2129398659961 is 1699568939212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1368534984336 + 760863675625 = 1169844^2 + 872275^2 .

It is a cyclic number.

It is not a de Polignac number, because 2129398659961 - 2³ = 2129398659953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2129398659931) 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, 14584922256 + ... + 14584922401.

It is an arithmetic number, because the mean of its divisors is an integer number (539642126173).

Almost surely, 2^{2129398659961} is an apocalyptic number.

It is an amenable number.

2129398659961 is a deficient number, since it is larger than the sum of its proper divisors (29169844731).

2129398659961 is an equidigital number, since it uses as much as digits as its factorization.

2129398659961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29169844730.

The product of its digits is 113374080, while the sum is 70.

The spelling of 2129398659961 in words is "two trillion, one hundred twenty-nine billion, three hundred ninety-eight million, six hundred fifty-nine thousand, nine hundred sixty-one".