1621228109 has 8 divisors (see below), whose sum is σ = 1661493120. Its totient is φ = 1580997600.

The previous prime is 1621228099. The next prime is 1621228123. The reversal of 1621228109 is 9018221261.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621228109 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621228709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104732 + ... + 119210.

It is an arithmetic number, because the mean of its divisors is an integer number (207686640).

Almost surely, 2^1621228109 is an apocalyptic number.

It is an amenable number.

1621228109 is a deficient number, since it is larger than the sum of its proper divisors (40265011).

1621228109 is a wasteful number, since it uses less digits than its factorization.

1621228109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17251.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 1621228109 is about 40264.4770113806. The cubic root of 1621228109 is about 1174.7570003603.

The spelling of 1621228109 in words is "one billion, six hundred twenty-one million, two hundred twenty-eight thousand, one hundred nine".