1664264161521 has 24 divisors (see below), whose sum is σ = 2596066724160. Its totient is φ = 1021309714656.

The previous prime is 1664264161517. The next prime is 1664264161529. The reversal of 1664264161521 is 1251614624661.

1664264161521 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 2 + 6 + 4 + 1 + 615 + 21 = 666.

It is not a de Polignac number, because 1664264161521 - 2² = 1664264161517 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1664264161529) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19769251 + ... + 19853256.

It is an arithmetic number, because the mean of its divisors is an integer number (108169446840).

Almost surely, 2^{1664264161521} is an apocalyptic number.

It is an amenable number.

1664264161521 is a deficient number, since it is larger than the sum of its proper divisors (931802562639).

1664264161521 is a wasteful number, since it uses less digits than its factorization.

1664264161521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39622885 (or 39622882 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The spelling of 1664264161521 in words is "one trillion, six hundred sixty-four billion, two hundred sixty-four million, one hundred sixty-one thousand, five hundred twenty-one".