1668157 has 4 divisors (see below), whose sum is σ = 1672000. Its totient is φ = 1664316.

The previous prime is 1668137. The next prime is 1668197. The reversal of 1668157 is 7518661.

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: 7518661 = 19 ⋅395719.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668157 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668137) 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, 1173 + ... + 2170.

It is an arithmetic number, because the mean of its divisors is an integer number (418000).

2^1668157 is an apocalyptic number.

It is an amenable number.

1668157 is a deficient number, since it is larger than the sum of its proper divisors (3843).

1668157 is an equidigital number, since it uses as much as digits as its factorization.

1668157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3842.

The product of its digits is 10080, while the sum is 34.

The square root of 1668157 is about 1291.5715233776. The cubic root of 1668157 is about 118.5984393323.

The spelling of 1668157 in words is "one million, six hundred sixty-eight thousand, one hundred fifty-seven".