2551721100361 has 4 divisors (see below), whose sum is σ = 2554398668052. Its totient is φ = 2549043532672.

The previous prime is 2551721100307. The next prime is 2551721100407. The reversal of 2551721100361 is 1630011271552.

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 471907172025 + 2079813928336 = 686955^2 + 1442156^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551721100361 - 2⁷ = 2551721100233 is a prime.

It is a super-2 number, since 2×2551721100361² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2551721100161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1338782416 + ... + 1338784321.

It is an arithmetic number, because the mean of its divisors is an integer number (638599667013).

Almost surely, 2^{2551721100361} is an apocalyptic number.

It is an amenable number.

2551721100361 is a deficient number, since it is larger than the sum of its proper divisors (2677567691).

2551721100361 is an equidigital number, since it uses as much as digits as its factorization.

2551721100361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2677567690.

The product of its (nonzero) digits is 12600, while the sum is 34.

The spelling of 2551721100361 in words is "two trillion, five hundred fifty-one billion, seven hundred twenty-one million, one hundred thousand, three hundred sixty-one".