66015440 has 20 divisors (see below), whose sum is σ = 153486084. Its totient is φ = 26406144.

The previous prime is 66015431. The next prime is 66015473. The reversal of 66015440 is 4451066.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 51208336 + 14807104 = 7156^2 + 3848^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 412517 + ... + 412676.

Almost surely, 2^66015440 is an apocalyptic number.

It is an amenable number.

66015440 is an abundant number, since it is smaller than the sum of its proper divisors (87470644).

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

66015440 is a wasteful number, since it uses less digits than its factorization.

66015440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825206 (or 825200 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 66015440 is about 8124.9886153766. The cubic root of 66015440 is about 404.1555131132.

The spelling of 66015440 in words is "sixty-six million, fifteen thousand, four hundred forty".