664725447 has 40 divisors (see below), whose sum is σ = 1015238400. Its totient is φ = 433305936.

The previous prime is 664725421. The next prime is 664725473. The reversal of 664725447 is 744527466.

664725447 is a `hidden beast` number, since 66 + 47 + 2 + 544 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (664725421) and next prime (664725473).

It is not a de Polignac number, because 664725447 - 2⁷ = 664725319 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664725547) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1753704 + ... + 1754082.

It is an arithmetic number, because the mean of its divisors is an integer number (25380960).

Almost surely, 2^664725447 is an apocalyptic number.

664725447 is a deficient number, since it is larger than the sum of its proper divisors (350512953).

664725447 is a wasteful number, since it uses less digits than its factorization.

664725447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817 (or 808 counting only the distinct ones).

The product of its digits is 1128960, while the sum is 45.

The square root of 664725447 is about 25782.2700125493. The cubic root of 664725447 is about 872.7317346274.

The spelling of 664725447 in words is "six hundred sixty-four million, seven hundred twenty-five thousand, four hundred forty-seven".