66021568 has 56 divisors (see below), whose sum is σ = 136940544. Its totient is φ = 31545600.

The previous prime is 66021563. The next prime is 66021583. The reversal of 66021568 is 86512066.

It is a super-3 number, since 3×66021568³ (a number of 24 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (66021563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 212133 + ... + 212443.

Almost surely, 2^66021568 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 66021568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68470272).

66021568 is an abundant number, since it is smaller than the sum of its proper divisors (70918976).

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

66021568 is a wasteful number, since it uses less digits than its factorization.

66021568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461 (or 451 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 66021568 is about 8125.3657148463. The cubic root of 66021568 is about 404.1680182097.

The spelling of 66021568 in words is "sixty-six million, twenty-one thousand, five hundred sixty-eight".