1666235640 has 32 divisors (see below), whose sum is σ = 4998707280. Its totient is φ = 444329472.

The previous prime is 1666235573. The next prime is 1666235651. The reversal of 1666235640 is 465326661.

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, 6942529 + ... + 6942768.

Almost surely, 2^1666235640 is an apocalyptic number.

1666235640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666235640 is an abundant number, since it is smaller than the sum of its proper divisors (3332471640).

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

1666235640 is a wasteful number, since it uses less digits than its factorization.

1666235640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13885311 (or 13885307 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 39.

The square root of 1666235640 is about 40819.5497280409. The cubic root of 1666235640 is about 1185.5288849603.

The spelling of 1666235640 in words is "one billion, six hundred sixty-six million, two hundred thirty-five thousand, six hundred forty".