66442920 has 128 divisors (see below), whose sum is σ = 210263040. Its totient is φ = 16773120.

The previous prime is 66442907. The next prime is 66442933. The reversal of 66442920 is 2924466.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66442907) and next prime (66442933).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 196992 + ... + 197328.

It is an arithmetic number, because the mean of its divisors is an integer number (1642680).

Almost surely, 2^66442920 is an apocalyptic number.

66442920 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 66442920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105131520).

66442920 is an abundant number, since it is smaller than the sum of its proper divisors (143820120).

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

66442920 is a wasteful number, since it uses less digits than its factorization.

66442920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435 (or 431 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 66442920 is about 8151.2526644682. The cubic root of 66442920 is about 405.0260004646.

The spelling of 66442920 in words is "sixty-six million, four hundred forty-two thousand, nine hundred twenty".