1645611623 has 2 divisors, whose sum is σ = 1645611624. Its totient is φ = 1645611622.

The previous prime is 1645611601. The next prime is 1645611647. The reversal of 1645611623 is 3261165461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1645611623 - 2⁶ = 1645611559 is a prime.

It is a super-2 number, since 2×1645611623² = 5416075227505388258, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645611673) 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, 822805811 + 822805812.

It is an arithmetic number, because the mean of its divisors is an integer number (822805812).

Almost surely, 2^1645611623 is an apocalyptic number.

1645611623 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645611623 is an equidigital number, since it uses as much as digits as its factorization.

1645611623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 35.

The square root of 1645611623 is about 40566.1388722171. The cubic root of 1645611623 is about 1180.6172254479.

The spelling of 1645611623 in words is "one billion, six hundred forty-five million, six hundred eleven thousand, six hundred twenty-three".