61668680400 has 240 divisors, whose sum is σ = 220321166400. Its totient is φ = 16383075840.

The previous prime is 61668680393. The next prime is 61668680417. The reversal of 61668680400 is 408686616.

61668680400 is a `hidden beast` number, since 6 + 166 + 8 + 6 + 80 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×61668680400² (a number of 22 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2894587 + ... + 2915813.

It is an arithmetic number, because the mean of its divisors is an integer number (918004860).

Almost surely, 2^61668680400 is an apocalyptic number.

61668680400 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 61668680400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110160583200).

61668680400 is an abundant number, since it is smaller than the sum of its proper divisors (158652486000).

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

61668680400 is a wasteful number, since it uses less digits than its factorization.

61668680400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21523 (or 21506 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 61668680400 in words is "sixty-one billion, six hundred sixty-eight million, six hundred eighty thousand, four hundred".