1621568723 has 2 divisors, whose sum is σ = 1621568724. Its totient is φ = 1621568722.

The previous prime is 1621568659. The next prime is 1621568777. The reversal of 1621568723 is 3278651261.

It is a strong prime.

It is an emirp because it is prime and its reverse (3278651261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621568723 - 2⁶ = 1621568659 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621568323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810784361 + 810784362.

It is an arithmetic number, because the mean of its divisors is an integer number (810784362).

Almost surely, 2^1621568723 is an apocalyptic number.

1621568723 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621568723 is an equidigital number, since it uses as much as digits as its factorization.

1621568723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 41.

The square root of 1621568723 is about 40268.7064977260. The cubic root of 1621568723 is about 1174.8392652925.

The spelling of 1621568723 in words is "one billion, six hundred twenty-one million, five hundred sixty-eight thousand, seven hundred twenty-three".