61655720100 has 288 divisors, whose sum is σ = 204518160000. Its totient is φ = 14214942720.

The previous prime is 61655720099. The next prime is 61655720117. The reversal of 61655720100 is 102755616.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6590226 + ... + 6599574.

It is an arithmetic number, because the mean of its divisors is an integer number (710132500).

Almost surely, 2^61655720100 is an apocalyptic number.

61655720100 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61655720100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102259080000).

61655720100 is an abundant number, since it is smaller than the sum of its proper divisors (142862439900).

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

61655720100 is a wasteful number, since it uses less digits than its factorization.

61655720100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9487 (or 9480 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 33.

The spelling of 61655720100 in words is "sixty-one billion, six hundred fifty-five million, seven hundred twenty thousand, one hundred".