61818544800 has 216 divisors, whose sum is σ = 220148526780. Its totient is φ = 16321536000.

The previous prime is 61818544793. The next prime is 61818544807. The reversal of 61818544800 is 844581816.

61818544800 is a `hidden beast` number, since 6 + 18 + 18 + 544 + 80 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (61818544793) and next prime (61818544807).

It can be written as a sum of positive squares in 6 ways, for example, as 41532809616 + 20285735184 = 203796^2 + 142428^2 .

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 (61818544807) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 684696 + ... + 769704.

Almost surely, 2^61818544800 is an apocalyptic number.

61818544800 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 61818544800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110074263390).

61818544800 is an abundant number, since it is smaller than the sum of its proper divisors (158329981980).

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

61818544800 is a wasteful number, since it uses less digits than its factorization.

61818544800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85136 (or 85120 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 45.

The spelling of 61818544800 in words is "sixty-one billion, eight hundred eighteen million, five hundred forty-four thousand, eight hundred".