66451540 has 12 divisors (see below), whose sum is σ = 139548276. Its totient is φ = 26580608.

The previous prime is 66451537. The next prime is 66451573. The reversal of 66451540 is 4515466.

It can be written as a sum of positive squares in 2 ways, for example, as 7683984 + 58767556 = 2772^2 + 7666^2 .

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, 1661269 + ... + 1661308.

It is an arithmetic number, because the mean of its divisors is an integer number (11629023).

Almost surely, 2^66451540 is an apocalyptic number.

It is an amenable number.

66451540 is an abundant number, since it is smaller than the sum of its proper divisors (73096736).

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

66451540 is a wasteful number, since it uses less digits than its factorization.

66451540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3322586 (or 3322584 counting only the distinct ones).

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

The square root of 66451540 is about 8151.7814004057. The cubic root of 66451540 is about 405.0435151130.

It can be divided in two parts, 6 and 6451540, that added together give a palindrome (6451546).

The spelling of 66451540 in words is "sixty-six million, four hundred fifty-one thousand, five hundred forty".