1621121 has 4 divisors (see below), whose sum is σ = 1633092. Its totient is φ = 1609152.

The previous prime is 1621097. The next prime is 1621127. The reversal of 1621121 is 1211261.

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 1290496 + 330625 = 1136^2 + 575^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621121 - 2¹⁴ = 1604737 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1621096 and 1621105.

It is not an unprimeable number, because it can be changed into a prime (1621127) 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, 5780 + ... + 6053.

It is an arithmetic number, because the mean of its divisors is an integer number (408273).

2^1621121 is an apocalyptic number.

It is an amenable number.

1621121 is a deficient number, since it is larger than the sum of its proper divisors (11971).

1621121 is a wasteful number, since it uses less digits than its factorization.

1621121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11970.

The product of its digits is 24, while the sum is 14.

The square root of 1621121 is about 1273.2325003706. The cubic root of 1621121 is about 117.4731129064.

Adding to 1621121 its reverse (1211261), we get a palindrome (2832382).

The spelling of 1621121 in words is "one million, six hundred twenty-one thousand, one hundred twenty-one".