1659421 has 4 divisors (see below), whose sum is σ = 1757052. Its totient is φ = 1561792.

The previous prime is 1659407. The next prime is 1659431. The reversal of 1659421 is 1249561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1249561 = 59 ⋅21179.

It can be written as a sum of positive squares in 2 ways, for example, as 1368900 + 290521 = 1170^2 + 539^2 .

It is a cyclic number.

It is not a de Polignac number, because 1659421 - 2¹³ = 1651229 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1659421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1659401) 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, 48790 + ... + 48823.

It is an arithmetic number, because the mean of its divisors is an integer number (439263).

2^1659421 is an apocalyptic number.

It is an amenable number.

1659421 is a deficient number, since it is larger than the sum of its proper divisors (97631).

1659421 is an equidigital number, since it uses as much as digits as its factorization.

1659421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97630.

The product of its digits is 2160, while the sum is 28.

The square root of 1659421 is about 1288.1851574987. The cubic root of 1659421 is about 118.3910468105.

It can be divided in two parts, 1659 and 421, that added together give a triangular number (2080 = T₆₄).

The spelling of 1659421 in words is "one million, six hundred fifty-nine thousand, four hundred twenty-one".