61661100 has 36 divisors (see below), whose sum is σ = 178406984. Its totient is φ = 16442880.

The previous prime is 61661087. The next prime is 61661111. The reversal of 61661100 is 116616.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 102469 + ... + 103068.

Almost surely, 2^61661100 is an apocalyptic number.

61661100 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61661100 is an abundant number, since it is smaller than the sum of its proper divisors (116745884).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61661100 is a wasteful number, since it uses less digits than its factorization.

61661100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205554 (or 205547 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 61661100 is about 7852.4582138334. The cubic root of 61661100 is about 395.0666981318.

Adding to 61661100 its reverse (116616), we get a palindrome (61777716).

It can be divided in two parts, 616 and 61100, that added together give a palindrome (61716).

The spelling of 61661100 in words is "sixty-one million, six hundred sixty-one thousand, one hundred".