66406240 has 24 divisors (see below), whose sum is σ = 156885120. Its totient is φ = 26562432.

The previous prime is 66406237. The next prime is 66406243. The reversal of 66406240 is 4260466.

It is an interprime number because it is at equal distance from previous prime (66406237) and next prime (66406243).

It is a junction number, because it is equal to n+sod(n) for n = 66406199 and 66406208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66406243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207360 + ... + 207679.

It is an arithmetic number, because the mean of its divisors is an integer number (6536880).

Almost surely, 2^66406240 is an apocalyptic number.

It is an amenable number.

66406240 is an abundant number, since it is smaller than the sum of its proper divisors (90478880).

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

66406240 is a wasteful number, since it uses less digits than its factorization.

66406240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415054 (or 415046 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 66406240 is about 8149.0023929313. The cubic root of 66406240 is about 404.9514548327.

It can be divided in two parts, 6640 and 6240, that added together give a triangular number (12880 = T₁₆₀).

The spelling of 66406240 in words is "sixty-six million, four hundred six thousand, two hundred forty".