66890105856 has 440 divisors, whose sum is σ = 238255079040. Its totient is φ = 18276876288.

The previous prime is 66890105831. The next prime is 66890105911. The reversal of 66890105856 is 65850109866.

It is a happy number.

It is a super-2 number, since 2×66890105856² (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 an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 13351480 + ... + 13356488.

It is an arithmetic number, because the mean of its divisors is an integer number (541488816).

Almost surely, 2^66890105856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66890105856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119127539520).

66890105856 is an abundant number, since it is smaller than the sum of its proper divisors (171364973184).

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

66890105856 is a wasteful number, since it uses less digits than its factorization.

66890105856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5071 (or 5044 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 54.

The spelling of 66890105856 in words is "sixty-six billion, eight hundred ninety million, one hundred five thousand, eight hundred fifty-six".