261553772444321 has 8 divisors (see below), whose sum is σ = 298918705276800. Its totient is φ = 224188866661248.

The previous prime is 261553772444317. The next prime is 261553772444401. The reversal of 261553772444321 is 123444277355162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261553772444321 - 2² = 261553772444317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261553772444621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22264145 + ... + 31918641.

It is an arithmetic number, because the mean of its divisors is an integer number (37364838159600).

Almost surely, 2^{261553772444321} is an apocalyptic number.

It is an amenable number.

261553772444321 is a deficient number, since it is larger than the sum of its proper divisors (37364932832479).

261553772444321 is an equidigital number, since it uses as much as digits as its factorization.

261553772444321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13524703.

The product of its digits is 33868800, while the sum is 56.

The spelling of 261553772444321 in words is "two hundred sixty-one trillion, five hundred fifty-three billion, seven hundred seventy-two million, four hundred forty-four thousand, three hundred twenty-one".