1668281437 has 4 divisors (see below), whose sum is σ = 1668461980. Its totient is φ = 1668100896.

The previous prime is 1668281429. The next prime is 1668281443. The reversal of 1668281437 is 7341828661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 663011001 + 1005270436 = 25749^2 + 31706^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668281437 - 2³ = 1668281429 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 (1668281467) 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, 75618 + ... + 95155.

It is an arithmetic number, because the mean of its divisors is an integer number (417115495).

Almost surely, 2^1668281437 is an apocalyptic number.

It is an amenable number.

1668281437 is a deficient number, since it is larger than the sum of its proper divisors (180543).

1668281437 is an equidigital number, since it uses as much as digits as its factorization.

1668281437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180542.

The product of its digits is 387072, while the sum is 46.

The square root of 1668281437 is about 40844.6010752951. The cubic root of 1668281437 is about 1186.0138822885.

The spelling of 1668281437 in words is "one billion, six hundred sixty-eight million, two hundred eighty-one thousand, four hundred thirty-seven".