61856618077 has 2 divisors, whose sum is σ = 61856618078. Its totient is φ = 61856618076.

The previous prime is 61856618023. The next prime is 61856618107. The reversal of 61856618077 is 77081665816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57718140516 + 4138477561 = 240246^2 + 64331^2 .

It is a cyclic number.

It is not a de Polignac number, because 61856618077 - 2¹⁵ = 61856585309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61856618777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30928309038 + 30928309039.

It is an arithmetic number, because the mean of its divisors is an integer number (30928309039).

Almost surely, 2^61856618077 is an apocalyptic number.

It is an amenable number.

61856618077 is a deficient number, since it is larger than the sum of its proper divisors (1).

61856618077 is an equidigital number, since it uses as much as digits as its factorization.

61856618077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3386880, while the sum is 55.

The spelling of 61856618077 in words is "sixty-one billion, eight hundred fifty-six million, six hundred eighteen thousand, seventy-seven".