61561613 has 2 divisors, whose sum is σ = 61561614. Its totient is φ = 61561612.

The previous prime is 61561601. The next prime is 61561631. The reversal of 61561613 is 31616516.

Together with next prime (61561631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49603849 + 11957764 = 7043^2 + 3458^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61561613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61561663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30780806 + 30780807.

It is an arithmetic number, because the mean of its divisors is an integer number (30780807).

Almost surely, 2^61561613 is an apocalyptic number.

It is an amenable number.

61561613 is a deficient number, since it is larger than the sum of its proper divisors (1).

61561613 is an equidigital number, since it uses as much as digits as its factorization.

61561613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 29.

The square root of 61561613 is about 7846.1208886940. The cubic root of 61561613 is about 394.8541105205.

It can be divided in two parts, 615616 and 13, that multiplied together give a palindrome (8003008).

The spelling of 61561613 in words is "sixty-one million, five hundred sixty-one thousand, six hundred thirteen".