1623664009991 has 2 divisors, whose sum is σ = 1623664009992. Its totient is φ = 1623664009990.

The previous prime is 1623664009969. The next prime is 1623664010099. The reversal of 1623664009991 is 1999004663261.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1623664009991 - 2¹⁴ = 1623663993607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1623664008991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 811832004995 + 811832004996.

It is an arithmetic number, because the mean of its divisors is an integer number (811832004996).

Almost surely, 2^{1623664009991} is an apocalyptic number.

1623664009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1623664009991 is an equidigital number, since it uses as much as digits as its factorization.

1623664009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3779136, while the sum is 56.

The spelling of 1623664009991 in words is "one trillion, six hundred twenty-three billion, six hundred sixty-four million, nine thousand, nine hundred ninety-one".