66985897440 has 384 divisors, whose sum is σ = 263560614912. Its totient is φ = 13893304320.

The previous prime is 66985897403. The next prime is 66985897471. The reversal of 66985897440 is 4479858966.

It is a super-2 number, since 2×66985897440² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24872734 + ... + 24875426.

It is an arithmetic number, because the mean of its divisors is an integer number (686355768).

Almost surely, 2^66985897440 is an apocalyptic number.

66985897440 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 66985897440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131780307456).

66985897440 is an abundant number, since it is smaller than the sum of its proper divisors (196574717472).

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

66985897440 is a wasteful number, since it uses less digits than its factorization.

66985897440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3402 (or 3394 counting only the distinct ones).

The product of its (nonzero) digits is 104509440, while the sum is 66.

The spelling of 66985897440 in words is "sixty-six billion, nine hundred eighty-five million, eight hundred ninety-seven thousand, four hundred forty".