1664036991947 has 32 divisors (see below), whose sum is σ = 1928935296000. Its totient is φ = 1419634944000.

The previous prime is 1664036991937. The next prime is 1664036991983. The reversal of 1664036991947 is 7491996304661.

It is a cyclic number.

It is not a de Polignac number, because 1664036991947 - 2²⁶ = 1663969883083 is a prime.

It is a super-2 number, since 2×1664036991947² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1664036991937) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11355947 + ... + 11501547.

It is an arithmetic number, because the mean of its divisors is an integer number (60279228000).

Almost surely, 2^{1664036991947} is an apocalyptic number.

1664036991947 is a deficient number, since it is larger than the sum of its proper divisors (264898304053).

1664036991947 is a wasteful number, since it uses less digits than its factorization.

1664036991947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146147.

The product of its (nonzero) digits is 52907904, while the sum is 65.

The spelling of 1664036991947 in words is "one trillion, six hundred sixty-four billion, thirty-six million, nine hundred ninety-one thousand, nine hundred forty-seven".