2542320561721 has 4 divisors (see below), whose sum is σ = 2611031928292. Its totient is φ = 2473609195152.

The previous prime is 2542320561709. The next prime is 2542320561727. The reversal of 2542320561721 is 1271650232452.

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 2032802983696 + 509517578025 = 1425764^2 + 713805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2542320561721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2542320561727) 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, 34355683230 + ... + 34355683303.

It is an arithmetic number, because the mean of its divisors is an integer number (652757982073).

Almost surely, 2^{2542320561721} is an apocalyptic number.

It is an amenable number.

2542320561721 is a deficient number, since it is larger than the sum of its proper divisors (68711366571).

2542320561721 is an equidigital number, since it uses as much as digits as its factorization.

2542320561721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68711366570.

The product of its (nonzero) digits is 201600, while the sum is 40.

The spelling of 2542320561721 in words is "two trillion, five hundred forty-two billion, three hundred twenty million, five hundred sixty-one thousand, seven hundred twenty-one".