61851780 has 216 divisors, whose sum is σ = 211203720. Its totient is φ = 14622720.

The previous prime is 61851773. The next prime is 61851791. The reversal of 61851780 is 8715816.

61851780 is a `hidden beast` number, since 61 + 8 + 517 + 80 = 666.

61851780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 12 ways, for example, as 11128896 + 50722884 = 3336^2 + 7122^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 1508560 + ... + 1508600.

It is an arithmetic number, because the mean of its divisors is an integer number (977795).

Almost surely, 2^61851780 is an apocalyptic number.

61851780 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 61851780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105601860).

61851780 is an abundant number, since it is smaller than the sum of its proper divisors (149351940).

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

61851780 is a wasteful number, since it uses less digits than its factorization.

61851780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 61851780 is about 7864.5902626901. The cubic root of 61851780 is about 395.4735121520.

The spelling of 61851780 in words is "sixty-one million, eight hundred fifty-one thousand, seven hundred eighty".