664612581555 has 48 divisors (see below), whose sum is σ = 1243373695200. Its totient is φ = 326465040384.

The previous prime is 664612581553. The next prime is 664612581557. The reversal of 664612581555 is 555185216466.

664612581555 is a `hidden beast` number, since 6 + 6 + 4 + 6 + 1 + 2 + 5 + 81 + 555 = 666.

It is an interprime number because it is at equal distance from previous prime (664612581553) and next prime (664612581557).

It is not a de Polignac number, because 664612581555 - 2¹ = 664612581553 is a prime.

It is a super-2 number, since 2×664612581555² (a number of 24 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (664612581551) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1002469 + ... + 1527798.

It is an arithmetic number, because the mean of its divisors is an integer number (25903618650).

Almost surely, 2^664612581555 is an apocalyptic number.

664612581555 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

664612581555 is a deficient number, since it is larger than the sum of its proper divisors (578761113645).

664612581555 is a wasteful number, since it uses less digits than its factorization.

664612581555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2530740 (or 2530737 counting only the distinct ones).

The product of its digits is 8640000, while the sum is 54.

The spelling of 664612581555 in words is "six hundred sixty-four billion, six hundred twelve million, five hundred eighty-one thousand, five hundred fifty-five".