61566613 has 2 divisors, whose sum is σ = 61566614. Its totient is φ = 61566612.

The previous prime is 61566611. The next prime is 61566643. The reversal of 61566613 is 31666516.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41692849 + 19873764 = 6457^2 + 4458^2 .

It is a cyclic number.

It is not a de Polignac number, because 61566613 - 2¹ = 61566611 is a prime.

Together with 61566611, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61566611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30783306 + 30783307.

It is an arithmetic number, because the mean of its divisors is an integer number (30783307).

Almost surely, 2^61566613 is an apocalyptic number.

It is an amenable number.

61566613 is a deficient number, since it is larger than the sum of its proper divisors (1).

61566613 is an equidigital number, since it uses as much as digits as its factorization.

61566613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 34.

The square root of 61566613 is about 7846.4395110139. The cubic root of 61566613 is about 394.8648001749.

It can be divided in two parts, 6156 and 6613, that added together give a square (12769 = 113²).

The spelling of 61566613 in words is "sixty-one million, five hundred sixty-six thousand, six hundred thirteen".