66540447 has 36 divisors (see below), whose sum is σ = 102842376. Its totient is φ = 42981840.

The previous prime is 66540443. The next prime is 66540457. The reversal of 66540447 is 74404566.

It is not a de Polignac number, because 66540447 - 2² = 66540443 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66540443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 993108 + ... + 993174.

Almost surely, 2^66540447 is an apocalyptic number.

66540447 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

66540447 is a deficient number, since it is larger than the sum of its proper divisors (36301929).

66540447 is an frugal number, since it uses more digits than its factorization.

66540447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 66540447 is about 8157.2328028566. The cubic root of 66540447 is about 405.2240735353.

The spelling of 66540447 in words is "sixty-six million, five hundred forty thousand, four hundred forty-seven".