61998891 has 8 divisors (see below), whose sum is σ = 82882560. Its totient is φ = 41223912.

The previous prime is 61998887. The next prime is 61998899. The reversal of 61998891 is 19889916.

It is a happy number.

61998891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61998891 - 2² = 61998887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61998899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25831 + ... + 28128.

It is an arithmetic number, because the mean of its divisors is an integer number (10360320).

Almost surely, 2^61998891 is an apocalyptic number.

61998891 is a deficient number, since it is larger than the sum of its proper divisors (20883669).

61998891 is a wasteful number, since it uses less digits than its factorization.

61998891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54345.

The product of its digits is 279936, while the sum is 51.

The square root of 61998891 is about 7873.9374521265. The cubic root of 61998891 is about 395.7868011143.

The spelling of 61998891 in words is "sixty-one million, nine hundred ninety-eight thousand, eight hundred ninety-one".