66349920 has 384 divisors, whose sum is σ = 270950400. Its totient is φ = 13547520.

The previous prime is 66349909. The next prime is 66349937. The reversal of 66349920 is 2994366.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

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, 2140305 + ... + 2140335.

It is an arithmetic number, because the mean of its divisors is an integer number (705600).

Almost surely, 2^66349920 is an apocalyptic number.

66349920 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 66349920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135475200).

66349920 is an abundant number, since it is smaller than the sum of its proper divisors (204600480).

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

66349920 is a wasteful number, since it uses less digits than its factorization.

66349920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 61 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 39.

The square root of 66349920 is about 8145.5460222136. The cubic root of 66349920 is about 404.8369409127.

The spelling of 66349920 in words is "sixty-six million, three hundred forty-nine thousand, nine hundred twenty".