2121605161723 has 4 divisors (see below), whose sum is σ = 2123913764560. Its totient is φ = 2119296558888.

The previous prime is 2121605161721. The next prime is 2121605161747. The reversal of 2121605161723 is 3271615061212.

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

It is a cyclic number.

It is not a de Polignac number, because 2121605161723 - 2¹ = 2121605161721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121605161721) 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, 1154300040 + ... + 1154301877.

It is an arithmetic number, because the mean of its divisors is an integer number (530978441140).

Almost surely, 2^{2121605161723} is an apocalyptic number.

2121605161723 is a deficient number, since it is larger than the sum of its proper divisors (2308602837).

2121605161723 is an equidigital number, since it uses as much as digits as its factorization.

2121605161723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2308602836.

The product of its (nonzero) digits is 30240, while the sum is 37.

The spelling of 2121605161723 in words is "two trillion, one hundred twenty-one billion, six hundred five million, one hundred sixty-one thousand, seven hundred twenty-three".