61666121149 has 2 divisors, whose sum is σ = 61666121150. Its totient is φ = 61666121148.

The previous prime is 61666121131. The next prime is 61666121183. The reversal of 61666121149 is 94112166616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50482001124 + 11184120025 = 224682^2 + 105755^2 .

It is a cyclic number.

It is not a de Polignac number, because 61666121149 - 2²¹ = 61664023997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61666121549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30833060574 + 30833060575.

It is an arithmetic number, because the mean of its divisors is an integer number (30833060575).

Almost surely, 2^61666121149 is an apocalyptic number.

It is an amenable number.

61666121149 is a deficient number, since it is larger than the sum of its proper divisors (1).

61666121149 is an equidigital number, since it uses as much as digits as its factorization.

61666121149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 43.

The spelling of 61666121149 in words is "sixty-one billion, six hundred sixty-six million, one hundred twenty-one thousand, one hundred forty-nine".