66406404 has 24 divisors (see below), whose sum is σ = 160292160. Its totient is φ = 21372064.

The previous prime is 66406367. The next prime is 66406409. The reversal of 66406404 is 40460466.

It is a super-2 number, since 2×66406404² = 8819620984422432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66406409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95064 + ... + 95759.

It is an arithmetic number, because the mean of its divisors is an integer number (6678840).

Almost surely, 2^66406404 is an apocalyptic number.

It is an amenable number.

66406404 is an abundant number, since it is smaller than the sum of its proper divisors (93885756).

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

66406404 is a wasteful number, since it uses less digits than its factorization.

66406404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190859 (or 190857 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 66406404 is about 8149.0124555065. The cubic root of 66406404 is about 404.9517881949.

It can be divided in two parts, 6 and 6406404, that added together give a triangular number (6406410 = T₃₅₇₉).

The spelling of 66406404 in words is "sixty-six million, four hundred six thousand, four hundred four".