61108991 has 4 divisors (see below), whose sum is σ = 61216584. Its totient is φ = 61001400.

The previous prime is 61108981. The next prime is 61109021. The reversal of 61108991 is 19980116.

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

It is a cyclic number.

It is not a de Polignac number, because 61108991 - 2¹⁴ = 61092607 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 (61108951) 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, 52940 + ... + 54081.

It is an arithmetic number, because the mean of its divisors is an integer number (15304146).

Almost surely, 2^61108991 is an apocalyptic number.

61108991 is a deficient number, since it is larger than the sum of its proper divisors (107593).

61108991 is a wasteful number, since it uses less digits than its factorization.

61108991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107592.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 61108991 is about 7817.2239957673. The cubic root of 61108991 is about 393.8840284134.

The spelling of 61108991 in words is "sixty-one million, one hundred eight thousand, nine hundred ninety-one".