61504781077 has 2 divisors, whose sum is σ = 61504781078. Its totient is φ = 61504781076.

The previous prime is 61504781057. The next prime is 61504781089. The reversal of 61504781077 is 77018740516.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59421862756 + 2082918321 = 243766^2 + 45639^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61504781077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61504781017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30752390538 + 30752390539.

It is an arithmetic number, because the mean of its divisors is an integer number (30752390539).

Almost surely, 2^61504781077 is an apocalyptic number.

It is an amenable number.

61504781077 is a deficient number, since it is larger than the sum of its proper divisors (1).

61504781077 is an equidigital number, since it uses as much as digits as its factorization.

61504781077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 329280, while the sum is 46.

The spelling of 61504781077 in words is "sixty-one billion, five hundred four million, seven hundred eighty-one thousand, seventy-seven".