61561655 has 4 divisors (see below), whose sum is σ = 73873992. Its totient is φ = 49249320.

The previous prime is 61561651. The next prime is 61561663. The reversal of 61561655 is 55616516.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 61561655 - 2² = 61561651 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561651) 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 in 3 ways as a sum of consecutive naturals, for example, 6156161 + ... + 6156170.

It is an arithmetic number, because the mean of its divisors is an integer number (18468498).

Almost surely, 2^61561655 is an apocalyptic number.

61561655 is a deficient number, since it is larger than the sum of its proper divisors (12312337).

61561655 is a wasteful number, since it uses less digits than its factorization.

61561655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12312336.

The product of its digits is 27000, while the sum is 35.

The square root of 61561655 is about 7846.1235651754. The cubic root of 61561655 is about 394.8542003160.

The spelling of 61561655 in words is "sixty-one million, five hundred sixty-one thousand, six hundred fifty-five".