276561820561 has 4 divisors (see below), whose sum is σ = 297835806772. Its totient is φ = 255287834352.

The previous prime is 276561820501. The next prime is 276561820571. The reversal of 276561820561 is 165028165672.

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 46958890000 + 229602930561 = 216700^2 + 479169^2 .

It is a cyclic number.

It is not a de Polignac number, because 276561820561 - 2⁷ = 276561820433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (276561820501) 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, 10636993086 + ... + 10636993111.

It is an arithmetic number, because the mean of its divisors is an integer number (74458951693).

Almost surely, 2^276561820561 is an apocalyptic number.

It is an amenable number.

276561820561 is a deficient number, since it is larger than the sum of its proper divisors (21273986211).

276561820561 is a wasteful number, since it uses less digits than its factorization.

276561820561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21273986210.

The product of its (nonzero) digits is 1209600, while the sum is 49.

The spelling of 276561820561 in words is "two hundred seventy-six billion, five hundred sixty-one million, eight hundred twenty thousand, five hundred sixty-one".