66969990 has 80 divisors (see below), whose sum is σ = 186349680. Its totient is φ = 17236800.

The previous prime is 66969989. The next prime is 66970039. The reversal of 66969990 is 9996966.

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

It is a congruent number.

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, 22065 + ... + 24915.

It is an arithmetic number, because the mean of its divisors is an integer number (2329371).

Almost surely, 2^66969990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66969990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93174840).

66969990 is an abundant number, since it is smaller than the sum of its proper divisors (119379690).

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

66969990 is a wasteful number, since it uses less digits than its factorization.

66969990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2899 (or 2890 counting only the distinct ones).

The product of its (nonzero) digits is 1417176, while the sum is 54.

The square root of 66969990 is about 8183.5194140419. The cubic root of 66969990 is about 406.0941606609.

The spelling of 66969990 in words is "sixty-six million, nine hundred sixty-nine thousand, nine hundred ninety".