61217856 has 210 divisors, whose sum is σ = 211972398. Its totient is φ = 17418240.

The previous prime is 61217851. The next prime is 61217857. The reversal of 61217856 is 65871216.

It can be written as a sum of positive squares in only one way, i.e., 57153600 + 4064256 = 7560^2 + 2016^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 61217856.

It is not an unprimeable number, because it can be changed into a prime (61217851) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 253896 + ... + 254136.

Almost surely, 2^61217856 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 61217856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105986199).

61217856 is an abundant number, since it is smaller than the sum of its proper divisors (150754542).

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

61217856 is a wasteful number, since it uses less digits than its factorization.

61217856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 253 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 61217856 is about 7824.1840469151. The cubic root of 61217856 is about 394.1177896854.

The spelling of 61217856 in words is "sixty-one million, two hundred seventeen thousand, eight hundred fifty-six".