1660421 has 4 divisors (see below), whose sum is σ = 1897632. Its totient is φ = 1423212.

The previous prime is 1660411. The next prime is 1660423. The reversal of 1660421 is 1240661.

It is a happy number.

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: 1240661 = 967 ⋅1283.

It is not a de Polignac number, because 1660421 - 2⁶ = 1660357 is a prime.

It is a super-3 number, since 3×1660421³ = 13733331616604395383, which contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1660393 and 1660402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660423) 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, 118595 + ... + 118608.

It is an arithmetic number, because the mean of its divisors is an integer number (474408).

2^1660421 is an apocalyptic number.

It is an amenable number.

1660421 is a deficient number, since it is larger than the sum of its proper divisors (237211).

1660421 is an equidigital number, since it uses as much as digits as its factorization.

1660421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237210.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1660421 is about 1288.5732420006. The cubic root of 1660421 is about 118.4148236325.

The spelling of 1660421 in words is "one million, six hundred sixty thousand, four hundred twenty-one".