66415540 has 12 divisors (see below), whose sum is σ = 139472676. Its totient is φ = 26566208.

The previous prime is 66415529. The next prime is 66415541. The reversal of 66415540 is 4551466.

It can be written as a sum of positive squares in 2 ways, for example, as 7033104 + 59382436 = 2652^2 + 7706^2 .

It is a super-2 number, since 2×66415540² = 8822047906983200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66415541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1660369 + ... + 1660408.

It is an arithmetic number, because the mean of its divisors is an integer number (11622723).

Almost surely, 2^66415540 is an apocalyptic number.

It is an amenable number.

66415540 is an abundant number, since it is smaller than the sum of its proper divisors (73057136).

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

66415540 is a wasteful number, since it uses less digits than its factorization.

66415540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3320786 (or 3320784 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 66415540 is about 8149.5729949489. The cubic root of 66415540 is about 404.9703580399.

The spelling of 66415540 in words is "sixty-six million, four hundred fifteen thousand, five hundred forty".