66091550400 has 672 divisors, whose sum is σ = 252109102080. Its totient is φ = 16826019840.

The previous prime is 66091550383. The next prime is 66091550509. The reversal of 66091550400 is 405519066.

66091550400 is a `hidden beast` number, since 6 + 60 + 9 + 1 + 550 + 40 + 0 = 666.

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 (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 87306822 + ... + 87307578.

Almost surely, 2^66091550400 is an apocalyptic number.

66091550400 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 66091550400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126054551040).

66091550400 is an abundant number, since it is smaller than the sum of its proper divisors (186017551680).

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

66091550400 is a wasteful number, since it uses less digits than its factorization.

66091550400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878 (or 857 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 66091550400 in words is "sixty-six billion, ninety-one million, five hundred fifty thousand, four hundred".