1664489771 has 24 divisors (see below), whose sum is σ = 2120865120. Its totient is φ = 1296460032.

The previous prime is 1664489767. The next prime is 1664489773. The reversal of 1664489771 is 1779844661.

It is not a de Polignac number, because 1664489771 - 2² = 1664489767 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1664489773) 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, 10295 + ... + 58608.

It is an arithmetic number, because the mean of its divisors is an integer number (88369380).

Almost surely, 2^1664489771 is an apocalyptic number.

1664489771 is a deficient number, since it is larger than the sum of its proper divisors (456375349).

1664489771 is a wasteful number, since it uses less digits than its factorization.

1664489771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68963 (or 68956 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 53.

The square root of 1664489771 is about 40798.1589167943. The cubic root of 1664489771 is about 1185.1146775498.

The spelling of 1664489771 in words is "one billion, six hundred sixty-four million, four hundred eighty-nine thousand, seven hundred seventy-one".