1621228123 has 2 divisors, whose sum is σ = 1621228124. Its totient is φ = 1621228122.

The previous prime is 1621228099. The next prime is 1621228157. The reversal of 1621228123 is 3218221261.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1621228123 - 2²⁵ = 1587673691 is a prime.

It is a super-2 number, since 2×1621228123² = 5256761253612206258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1621228091 and 1621228100.

It is not a weakly prime, because it can be changed into another prime (1621228723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810614061 + 810614062.

It is an arithmetic number, because the mean of its divisors is an integer number (810614062).

Almost surely, 2^1621228123 is an apocalyptic number.

1621228123 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621228123 is an equidigital number, since it uses as much as digits as its factorization.

1621228123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 28.

The square root of 1621228123 is about 40264.4771852312. The cubic root of 1621228123 is about 1174.7570037418.

Adding to 1621228123 its reverse (3218221261), we get a palindrome (4839449384).

The spelling of 1621228123 in words is "one billion, six hundred twenty-one million, two hundred twenty-eight thousand, one hundred twenty-three".