66540042 has 20 divisors (see below), whose sum is σ = 149099346. Its totient is φ = 22179960.

The previous prime is 66540029. The next prime is 66540053. The reversal of 66540042 is 24004566.

It is a happy number.

66540042 is a `hidden beast` number, since 6 + 654 + 0 + 0 + 4 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 62583921 + 3956121 = 7911^2 + 1989^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 66539988 and 66540015.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 205209 + ... + 205532.

Almost surely, 2^66540042 is an apocalyptic number.

66540042 is an abundant number, since it is smaller than the sum of its proper divisors (82559304).

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

66540042 is a wasteful number, since it uses less digits than its factorization.

66540042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410755 (or 410746 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 66540042 is about 8157.2079782239. The cubic root of 66540042 is about 405.2232513983.

The spelling of 66540042 in words is "sixty-six million, five hundred forty thousand, forty-two".