61891543998 has 12 divisors (see below), whose sum is σ = 134098345368. Its totient is φ = 20630514660.

The previous prime is 61891543997. The next prime is 61891544069. The reversal of 61891543998 is 89934519816.

61891543998 is a `hidden beast` number, since 6 + 1 + 89 + 1 + 543 + 9 + 9 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61891543991) 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 5 ways as a sum of consecutive naturals, for example, 1719209538 + ... + 1719209573.

It is an arithmetic number, because the mean of its divisors is an integer number (11174862114).

Almost surely, 2^61891543998 is an apocalyptic number.

61891543998 is an abundant number, since it is smaller than the sum of its proper divisors (72206801370).

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

61891543998 is a wasteful number, since it uses less digits than its factorization.

61891543998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3438419119 (or 3438419116 counting only the distinct ones).

The product of its digits is 16796160, while the sum is 63.

The spelling of 61891543998 in words is "sixty-one billion, eight hundred ninety-one million, five hundred forty-three thousand, nine hundred ninety-eight".