1666121 has 4 divisors (see below), whose sum is σ = 1704912. Its totient is φ = 1627332.

The previous prime is 1666111. The next prime is 1666127. The reversal of 1666121 is 1216661.

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: 1216661 = 881 ⋅1381.

It is a cyclic number.

It is not a de Polignac number, because 1666121 - 2¹⁴ = 1649737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666127) 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, 19331 + ... + 19416.

It is an arithmetic number, because the mean of its divisors is an integer number (426228).

2^1666121 is an apocalyptic number.

It is an amenable number.

1666121 is a deficient number, since it is larger than the sum of its proper divisors (38791).

1666121 is an equidigital number, since it uses as much as digits as its factorization.

It is an anagram of its base 8 representation: 1666121 = (6266111)₈.

1666121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38790.

The product of its digits is 432, while the sum is 23.

The square root of 1666121 is about 1290.7830956439. The cubic root of 1666121 is about 118.5501695499.

The spelling of 1666121 in words is "one million, six hundred sixty-six thousand, one hundred twenty-one".