61566389 has 2 divisors, whose sum is σ = 61566390. Its totient is φ = 61566388.

The previous prime is 61566383. The next prime is 61566397. The reversal of 61566389 is 98366516.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45900625 + 15665764 = 6775^2 + 3958^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61566389 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61566383) 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, 30783194 + 30783195.

It is an arithmetic number, because the mean of its divisors is an integer number (30783195).

Almost surely, 2^61566389 is an apocalyptic number.

It is an amenable number.

61566389 is a deficient number, since it is larger than the sum of its proper divisors (1).

61566389 is an equidigital number, since it uses as much as digits as its factorization.

61566389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 233280, while the sum is 44.

The square root of 61566389 is about 7846.4252370108. The cubic root of 61566389 is about 394.8643212908.

The spelling of 61566389 in words is "sixty-one million, five hundred sixty-six thousand, three hundred eighty-nine".