66399408 has 60 divisors (see below), whose sum is σ = 186717960. Its totient is φ = 22027008.

The previous prime is 66399401. The next prime is 66399409. The reversal of 66399408 is 80499366.

66399408 is a `hidden beast` number, since 6 + 639 + 9 + 4 + 0 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (66399401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32563 + ... + 34541.

It is an arithmetic number, because the mean of its divisors is an integer number (3111966).

Almost surely, 2^66399408 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 66399408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93358980).

66399408 is an abundant number, since it is smaller than the sum of its proper divisors (120318552).

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

66399408 is a wasteful number, since it uses less digits than its factorization.

66399408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226 (or 2217 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 66399408 is about 8148.5831897330. The cubic root of 66399408 is about 404.9375669650.

The spelling of 66399408 in words is "sixty-six million, three hundred ninety-nine thousand, four hundred eight".