2978558368661 has 2 divisors, whose sum is σ = 2978558368662. Its totient is φ = 2978558368660.

The previous prime is 2978558368547. The next prime is 2978558368699. The reversal of 2978558368661 is 1668638558792.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1621522092100 + 1357036276561 = 1273390^2 + 1164919^2 .

It is a cyclic number.

It is not a de Polignac number, because 2978558368661 - 2¹⁰ = 2978558367637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2978558365661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1489279184330 + 1489279184331.

It is an arithmetic number, because the mean of its divisors is an integer number (1489279184331).

Almost surely, 2^{2978558368661} is an apocalyptic number.

It is an amenable number.

2978558368661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2978558368661 is an equidigital number, since it uses as much as digits as its factorization.

2978558368661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1045094400, while the sum is 74.

The spelling of 2978558368661 in words is "two trillion, nine hundred seventy-eight billion, five hundred fifty-eight million, three hundred sixty-eight thousand, six hundred sixty-one".