61566139 has 2 divisors, whose sum is σ = 61566140. Its totient is φ = 61566138.

The previous prime is 61566119. The next prime is 61566157. The reversal of 61566139 is 93166516.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61566139 - 2⁵ = 61566107 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61566098 and 61566107.

It is not a weakly prime, because it can be changed into another prime (61566119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30783069 + 30783070.

It is an arithmetic number, because the mean of its divisors is an integer number (30783070).

Almost surely, 2^61566139 is an apocalyptic number.

61566139 is a deficient number, since it is larger than the sum of its proper divisors (1).

61566139 is an equidigital number, since it uses as much as digits as its factorization.

61566139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 37.

The square root of 61566139 is about 7846.4093061731. The cubic root of 61566139 is about 394.8637868205.

The spelling of 61566139 in words is "sixty-one million, five hundred sixty-six thousand, one hundred thirty-nine".