1621165939 has 2 divisors, whose sum is σ = 1621165940. Its totient is φ = 1621165938.

The previous prime is 1621165921. The next prime is 1621165943. The reversal of 1621165939 is 9395611261.

It is a strong prime.

It is an emirp because it is prime and its reverse (9395611261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621165939 - 2⁵ = 1621165907 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1621165895 and 1621165904.

It is not a weakly prime, because it can be changed into another prime (1621160939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810582969 + 810582970.

It is an arithmetic number, because the mean of its divisors is an integer number (810582970).

Almost surely, 2^1621165939 is an apocalyptic number.

1621165939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621165939 is an equidigital number, since it uses as much as digits as its factorization.

1621165939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 43.

The square root of 1621165939 is about 40263.7049835208. The cubic root of 1621165939 is about 1174.7419838478.

The spelling of 1621165939 in words is "one billion, six hundred twenty-one million, one hundred sixty-five thousand, nine hundred thirty-nine".