61289561 has 2 divisors, whose sum is σ = 61289562. Its totient is φ = 61289560.

The previous prime is 61289533. The next prime is 61289563. The reversal of 61289561 is 16598216.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58905625 + 2383936 = 7675^2 + 1544^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61289561 is a prime.

Together with 61289563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (61289563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30644780 + 30644781.

It is an arithmetic number, because the mean of its divisors is an integer number (30644781).

Almost surely, 2^61289561 is an apocalyptic number.

It is an amenable number.

61289561 is a deficient number, since it is larger than the sum of its proper divisors (1).

61289561 is an equidigital number, since it uses as much as digits as its factorization.

61289561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 38.

The square root of 61289561 is about 7828.7649728421. The cubic root of 61289561 is about 394.2716074946.

The spelling of 61289561 in words is "sixty-one million, two hundred eighty-nine thousand, five hundred sixty-one".