1621343123 has 4 divisors (see below), whose sum is σ = 1624845408. Its totient is φ = 1617840840.

The previous prime is 1621343111. The next prime is 1621343167. The reversal of 1621343123 is 3213431261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3213431261 = 61 ⋅52679201.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621343123 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1621343092 and 1621343101.

It is not an unprimeable number, because it can be changed into a prime (1621343923) 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, 1750448 + ... + 1751373.

It is an arithmetic number, because the mean of its divisors is an integer number (406211352).

Almost surely, 2^1621343123 is an apocalyptic number.

1621343123 is a deficient number, since it is larger than the sum of its proper divisors (3502285).

1621343123 is an equidigital number, since it uses as much as digits as its factorization.

1621343123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502284.

The product of its digits is 2592, while the sum is 26.

The square root of 1621343123 is about 40265.9052176901. The cubic root of 1621343123 is about 1174.7847797756.

Adding to 1621343123 its reverse (3213431261), we get a palindrome (4834774384).

The spelling of 1621343123 in words is "one billion, six hundred twenty-one million, three hundred forty-three thousand, one hundred twenty-three".