66909542400 has 576 divisors, whose sum is σ = 254397780000. Its totient is φ = 17216962560.

The previous prime is 66909542389. The next prime is 66909542411. The reversal of 66909542400 is 424590966.

66909542400 is a `hidden beast` number, since 6 + 69 + 0 + 9 + 542 + 40 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66909542389) and next prime (66909542411).

It is a tau number, because it is divible by the number of its divisors (576).

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, 40088766 + ... + 40090434.

Almost surely, 2^66909542400 is an apocalyptic number.

66909542400 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 66909542400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127198890000).

66909542400 is an abundant number, since it is smaller than the sum of its proper divisors (187488237600).

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

66909542400 is a wasteful number, since it uses less digits than its factorization.

66909542400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1739 (or 1708 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 66909542400 in words is "sixty-six billion, nine hundred nine million, five hundred forty-two thousand, four hundred".