1664763397 has 4 divisors (see below), whose sum is σ = 1816105536. Its totient is φ = 1513421260.

The previous prime is 1664763379. The next prime is 1664763409. The reversal of 1664763397 is 7933674661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7933674661 = 11 ⋅721243151.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1664763397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664763307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75671053 + ... + 75671074.

It is an arithmetic number, because the mean of its divisors is an integer number (454026384).

Almost surely, 2^1664763397 is an apocalyptic number.

It is an amenable number.

1664763397 is a deficient number, since it is larger than the sum of its proper divisors (151342139).

1664763397 is a wasteful number, since it uses less digits than its factorization.

1664763397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151342138.

The product of its digits is 3429216, while the sum is 52.

The square root of 1664763397 is about 40801.5121901137. The cubic root of 1664763397 is about 1185.1796144505.

The spelling of 1664763397 in words is "one billion, six hundred sixty-four million, seven hundred sixty-three thousand, three hundred ninety-seven".