1220621 has 4 divisors (see below), whose sum is σ = 1224192. Its totient is φ = 1217052.

The previous prime is 1220599. The next prime is 1220623. The reversal of 1220621 is 1260221.

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: 1260221 = 127 ⋅9923.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220621 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220596 and 1220605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1211 + ... + 1976.

It is an arithmetic number, because the mean of its divisors is an integer number (306048).

2^1220621 is an apocalyptic number.

It is an amenable number.

1220621 is a deficient number, since it is larger than the sum of its proper divisors (3571).

1220621 is an equidigital number, since it uses as much as digits as its factorization.

1220621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3570.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1220621 is about 1104.8171794464. The cubic root of 1220621 is about 106.8710999113.

Adding to 1220621 its reverse (1260221), we get a palindrome (2480842).

The spelling of 1220621 in words is "one million, two hundred twenty thousand, six hundred twenty-one".