1659666440 has 32 divisors (see below), whose sum is σ = 3743691480. Its totient is φ = 662188032.

The previous prime is 1659666439. The next prime is 1659666443. The reversal of 1659666440 is 446669561.

It can be written as a sum of positive squares in 4 ways, for example, as 1123188196 + 536478244 = 33514^2 + 23162^2 .

It is not an unprimeable number, because it can be changed into a prime (1659666443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36377 + ... + 68136.

Almost surely, 2^1659666440 is an apocalyptic number.

1659666440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1659666440 is an abundant number, since it is smaller than the sum of its proper divisors (2084025040).

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

1659666440 is a wasteful number, since it uses less digits than its factorization.

1659666440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104921 (or 104917 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 47.

The square root of 1659666440 is about 40739.0039151671. The cubic root of 1659666440 is about 1183.9688347805.

The spelling of 1659666440 in words is "one billion, six hundred fifty-nine million, six hundred sixty-six thousand, four hundred forty".