1664707973 has 2 divisors, whose sum is σ = 1664707974. Its totient is φ = 1664707972.

The previous prime is 1664707969. The next prime is 1664707981. The reversal of 1664707973 is 3797074661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1286872129 + 377835844 = 35873^2 + 19438^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664707973 - 2² = 1664707969 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1664707273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832353986 + 832353987.

It is an arithmetic number, because the mean of its divisors is an integer number (832353987).

Almost surely, 2^1664707973 is an apocalyptic number.

It is an amenable number.

1664707973 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664707973 is an equidigital number, since it uses as much as digits as its factorization.

1664707973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1333584, while the sum is 50.

The square root of 1664707973 is about 40800.8329939476. The cubic root of 1664707973 is about 1185.1664618059.

The spelling of 1664707973 in words is "one billion, six hundred sixty-four million, seven hundred seven thousand, nine hundred seventy-three".