61188720840 has 256 divisors, whose sum is σ = 232573420800. Its totient is φ = 14175793152.

The previous prime is 61188720833. The next prime is 61188720847. The reversal of 61188720840 is 4802788116.

61188720840 is a `hidden beast` number, since 611 + 8 + 8 + 7 + 20 + 8 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (61188720833) and next prime (61188720847).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (61188720847) 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 63 ways as a sum of consecutive naturals, for example, 110499 + ... + 366861.

It is an arithmetic number, because the mean of its divisors is an integer number (908489925).

Almost surely, 2^61188720840 is an apocalyptic number.

61188720840 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 61188720840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116286710400).

61188720840 is an abundant number, since it is smaller than the sum of its proper divisors (171384699960).

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

61188720840 is a wasteful number, since it uses less digits than its factorization.

61188720840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256413 (or 256403 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 45.

The spelling of 61188720840 in words is "sixty-one billion, one hundred eighty-eight million, seven hundred twenty thousand, eight hundred forty".