1664265940 has 24 divisors (see below), whose sum is σ = 3517225992. Its totient is φ = 661464960.

The previous prime is 1664265931. The next prime is 1664265959. The reversal of 1664265940 is 495624661.

It can be written as a sum of positive squares in 4 ways, for example, as 234518596 + 1429747344 = 15314^2 + 37812^2 .

It is a super-2 number, since 2×1664265940² = 5539562238088167200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261871 + ... + 268150.

It is an arithmetic number, because the mean of its divisors is an integer number (146551083).

Almost surely, 2^1664265940 is an apocalyptic number.

1664265940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664265940 is an abundant number, since it is smaller than the sum of its proper divisors (1852960052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1664265940 is a wasteful number, since it uses less digits than its factorization.

1664265940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530187 (or 530185 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 43.

The square root of 1664265940 is about 40795.4156738230. The cubic root of 1664265940 is about 1185.0615527025.

The spelling of 1664265940 in words is "one billion, six hundred sixty-four million, two hundred sixty-five thousand, nine hundred forty".