1622721 has 4 divisors (see below), whose sum is σ = 2163632. Its totient is φ = 1081812.

The previous prime is 1622711. The next prime is 1622729. The reversal of 1622721 is 1272261.

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.

It is not a de Polignac number, because 1622721 - 2⁹ = 1622209 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1622729) 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, 270451 + ... + 270456.

It is an arithmetic number, because the mean of its divisors is an integer number (540908).

2^1622721 is an apocalyptic number.

It is an amenable number.

1622721 is a deficient number, since it is larger than the sum of its proper divisors (540911).

1622721 is an equidigital number, since it uses as much as digits as its factorization.

1622721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540910.

The product of its digits is 336, while the sum is 21.

The square root of 1622721 is about 1273.8606674201. The cubic root of 1622721 is about 117.5117477314.

Adding to 1622721 its reverse (1272261), we get a palindrome (2894982).

The spelling of 1622721 in words is "one million, six hundred twenty-two thousand, seven hundred twenty-one".