61865856 has 256 divisors, whose sum is σ = 210772800. Its totient is φ = 17915904.

The previous prime is 61865851. The next prime is 61865861. The reversal of 61865856 is 65856816.

61865856 is a `hidden beast` number, since 61 + 8 + 6 + 585 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (61865851) and next prime (61865861).

It is a super-2 number, since 2×61865856² = 7654768277225472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61865851) 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 31 ways as a sum of consecutive naturals, for example, 3639160 + ... + 3639176.

Almost surely, 2^61865856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61865856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105386400).

61865856 is an abundant number, since it is smaller than the sum of its proper divisors (148906944).

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

61865856 is an equidigital number, since it uses as much as digits as its factorization.

61865856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65 (or 35 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The square root of 61865856 is about 7865.4851090063. The cubic root of 61865856 is about 395.5035100110.

The spelling of 61865856 in words is "sixty-one million, eight hundred sixty-five thousand, eight hundred fifty-six".