61665555 has 32 divisors (see below), whose sum is σ = 113186304. Its totient is φ = 28083456.

The previous prime is 61665533. The next prime is 61665557. The reversal of 61665555 is 55556616.

It is not a de Polignac number, because 61665555 - 2⁸ = 61665299 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (61665557) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31279 + ... + 33191.

It is an arithmetic number, because the mean of its divisors is an integer number (3537072).

Almost surely, 2^61665555 is an apocalyptic number.

61665555 is a deficient number, since it is larger than the sum of its proper divisors (51520749).

61665555 is a wasteful number, since it uses less digits than its factorization.

61665555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2235.

The product of its digits is 135000, while the sum is 39.

The square root of 61665555 is about 7852.7418778411. The cubic root of 61665555 is about 395.0762123948.

The spelling of 61665555 in words is "sixty-one million, six hundred sixty-five thousand, five hundred fifty-five".