1664871501 has 4 divisors (see below), whose sum is σ = 2219828672. Its totient is φ = 1109914332.

The previous prime is 1664871497. The next prime is 1664871521. The reversal of 1664871501 is 1051784661.

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: 1051784661 = 3 ⋅350594887.

It is not a de Polignac number, because 1664871501 - 2² = 1664871497 is a prime.

It is a super-2 number, since 2×1664871501² = 5543594229683986002, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1664871501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664871521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 277478581 + ... + 277478586.

It is an arithmetic number, because the mean of its divisors is an integer number (554957168).

Almost surely, 2^1664871501 is an apocalyptic number.

It is an amenable number.

1664871501 is a deficient number, since it is larger than the sum of its proper divisors (554957171).

1664871501 is an equidigital number, since it uses as much as digits as its factorization.

1664871501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554957170.

The product of its (nonzero) digits is 40320, while the sum is 39.

The square root of 1664871501 is about 40802.8369234297. The cubic root of 1664871501 is about 1185.2052677223.

The spelling of 1664871501 in words is "one billion, six hundred sixty-four million, eight hundred seventy-one thousand, five hundred one".