1621220 has 24 divisors (see below), whose sum is σ = 3441984. Its totient is φ = 641376.

The previous prime is 1621219. The next prime is 1621231. The reversal of 1621220 is 221261.

It is a junction number, because it is equal to n+sod(n) for n = 1621195 and 1621204.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1667 + ... + 2453.

It is an arithmetic number, because the mean of its divisors is an integer number (143416).

2^1621220 is an apocalyptic number.

1621220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621220 is an abundant number, since it is smaller than the sum of its proper divisors (1820764).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1621220 is a wasteful number, since it uses less digits than its factorization.

1621220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 899 (or 897 counting only the distinct ones).

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

The square root of 1621220 is about 1273.2713772013. The cubic root of 1621220 is about 117.4755041738.

Adding to 1621220 its reverse (221261), we get a palindrome (1842481).

The spelling of 1621220 in words is "one million, six hundred twenty-one thousand, two hundred twenty".