809797621 has 2 divisors, whose sum is σ = 809797622. Its totient is φ = 809797620.

The previous prime is 809797609. The next prime is 809797643. The reversal of 809797621 is 126797908.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 454286596 + 355511025 = 21314^2 + 18855^2 .

It is a cyclic number.

It is not a de Polignac number, because 809797621 - 2¹³ = 809789429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809717621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404898810 + 404898811.

It is an arithmetic number, because the mean of its divisors is an integer number (404898811).

Almost surely, 2^809797621 is an apocalyptic number.

It is an amenable number.

809797621 is a deficient number, since it is larger than the sum of its proper divisors (1).

809797621 is an equidigital number, since it uses as much as digits as its factorization.

809797621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 49.

The square root of 809797621 is about 28456.9432827913. The cubic root of 809797621 is about 932.0921109236.

The spelling of 809797621 in words is "eight hundred nine million, seven hundred ninety-seven thousand, six hundred twenty-one".