2978204645561 has 2 divisors, whose sum is σ = 2978204645562. Its totient is φ = 2978204645560.

The previous prime is 2978204645557. The next prime is 2978204645587. The reversal of 2978204645561 is 1655464028792.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1685697142336 + 1292507503225 = 1298344^2 + 1136885^2 .

It is a cyclic number.

It is not a de Polignac number, because 2978204645561 - 2² = 2978204645557 is a prime.

It is a super-2 number, since 2×2978204645561² (a number of 26 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2978204645561.

It is not a weakly prime, because it can be changed into another prime (2978204645551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1489102322780 + 1489102322781.

It is an arithmetic number, because the mean of its divisors is an integer number (1489102322781).

Almost surely, 2^{2978204645561} is an apocalyptic number.

It is an amenable number.

2978204645561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2978204645561 is an equidigital number, since it uses as much as digits as its factorization.

2978204645561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29030400, while the sum is 59.

The spelling of 2978204645561 in words is "two trillion, nine hundred seventy-eight billion, two hundred four million, six hundred forty-five thousand, five hundred sixty-one".