66216408 has 64 divisors (see below), whose sum is σ = 170380800. Its totient is φ = 21436800.

The previous prime is 66216407. The next prime is 66216413. The reversal of 66216408 is 80461266.

It is a happy number.

It is a super-2 number, since 2×66216408² = 8769225376844928, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66216401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142785 + ... + 143247.

It is an arithmetic number, because the mean of its divisors is an integer number (2662200).

Almost surely, 2^66216408 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 66216408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85190400).

66216408 is an abundant number, since it is smaller than the sum of its proper divisors (104164392).

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

66216408 is a wasteful number, since it uses less digits than its factorization.

66216408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632 (or 628 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 66216408 is about 8137.3464962480. The cubic root of 66216408 is about 404.5652154682.

The spelling of 66216408 in words is "sixty-six million, two hundred sixteen thousand, four hundred eight".