1621840823 has 2 divisors, whose sum is σ = 1621840824. Its totient is φ = 1621840822.

The previous prime is 1621840807. The next prime is 1621840861. The reversal of 1621840823 is 3280481261.

It is a weak prime.

It is an emirp because it is prime and its reverse (3280481261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621840823 - 2⁴ = 1621840807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1621840223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810920411 + 810920412.

It is an arithmetic number, because the mean of its divisors is an integer number (810920412).

Almost surely, 2^1621840823 is an apocalyptic number.

1621840823 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621840823 is an equidigital number, since it uses as much as digits as its factorization.

1621840823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 1621840823 is about 40272.0849100217. The cubic root of 1621840823 is about 1174.9049744791.

The spelling of 1621840823 in words is "one billion, six hundred twenty-one million, eight hundred forty thousand, eight hundred twenty-three".