61553566 has 16 divisors (see below), whose sum is σ = 102013344. Its totient is φ = 27706624.

The previous prime is 61553563. The next prime is 61553567. The reversal of 61553566 is 66535516.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61553563) 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 7 ways as a sum of consecutive naturals, for example, 38575 + ... + 40138.

It is an arithmetic number, because the mean of its divisors is an integer number (6375834).

Almost surely, 2^61553566 is an apocalyptic number.

61553566 is a deficient number, since it is larger than the sum of its proper divisors (40459778).

61553566 is a wasteful number, since it uses less digits than its factorization.

61553566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78755.

The product of its digits is 81000, while the sum is 37.

The square root of 61553566 is about 7845.6080707616. The cubic root of 61553566 is about 394.8369053752.

The spelling of 61553566 in words is "sixty-one million, five hundred fifty-three thousand, five hundred sixty-six".