66998534400 has 1080 divisors, whose sum is σ = 291347672000. Its totient is φ = 14870200320.

The previous prime is 66998534399. The next prime is 66998534401. The reversal of 66998534400 is 443589966.

66998534400 is a `hidden beast` number, since 6 + 69 + 9 + 8 + 534 + 40 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66998534399) and next prime (66998534401).

It is a tau number, because it is divible by the number of its divisors (1080).

It is a super-2 number, since 2×66998534400² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (66998534401) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 134265351 + ... + 134265849.

Almost surely, 2^66998534400 is an apocalyptic number.

66998534400 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 66998534400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145673836000).

66998534400 is an abundant number, since it is smaller than the sum of its proper divisors (224349137600).

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

66998534400 is a wasteful number, since it uses less digits than its factorization.

66998534400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581 (or 553 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 66998534400 in words is "sixty-six billion, nine hundred ninety-eight million, five hundred thirty-four thousand, four hundred".