66117870 has 288 divisors, whose sum is σ = 230211072. Its totient is φ = 13343616.

The previous prime is 66117869. The next prime is 66117889. The reversal of 66117870 is 7871166.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2874679 + ... + 2874701.

It is an arithmetic number, because the mean of its divisors is an integer number (799344).

Almost surely, 2^66117870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66117870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115105536).

66117870 is an abundant number, since it is smaller than the sum of its proper divisors (164093202).

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

66117870 is a wasteful number, since it uses less digits than its factorization.

66117870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 66117870 is about 8131.2895656224. The cubic root of 66117870 is about 404.3644352314.

The spelling of 66117870 in words is "sixty-six million, one hundred seventeen thousand, eight hundred seventy".