16841815621 has 2 divisors, whose sum is σ = 16841815622. Its totient is φ = 16841815620.

The previous prime is 16841815607. The next prime is 16841815643. The reversal of 16841815621 is 12651814861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12404390625 + 4437424996 = 111375^2 + 66614^2 .

It is a cyclic number.

It is not a de Polignac number, because 16841815621 - 2²⁹ = 16304944709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16841815691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8420907810 + 8420907811.

It is an arithmetic number, because the mean of its divisors is an integer number (8420907811).

Almost surely, 2^16841815621 is an apocalyptic number.

It is an amenable number.

16841815621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16841815621 is an equidigital number, since it uses as much as digits as its factorization.

16841815621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 92160, while the sum is 43.

The spelling of 16841815621 in words is "sixteen billion, eight hundred forty-one million, eight hundred fifteen thousand, six hundred twenty-one".