6801816521 has 2 divisors, whose sum is σ = 6801816522. Its totient is φ = 6801816520.

The previous prime is 6801816493. The next prime is 6801816559. The reversal of 6801816521 is 1256181086.

It is an a-pointer prime, because the next prime (6801816559) can be obtained adding 6801816521 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5628000400 + 1173816121 = 75020^2 + 34261^2 .

It is a cyclic number.

It is not a de Polignac number, because 6801816521 - 2¹⁰ = 6801815497 is a prime.

It is not a weakly prime, because it can be changed into another prime (6801846521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3400908260 + 3400908261.

It is an arithmetic number, because the mean of its divisors is an integer number (3400908261).

Almost surely, 2^6801816521 is an apocalyptic number.

It is an amenable number.

6801816521 is a deficient number, since it is larger than the sum of its proper divisors (1).

6801816521 is an equidigital number, since it uses as much as digits as its factorization.

6801816521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23040, while the sum is 38.

The square root of 6801816521 is about 82473.1260532787. The cubic root of 6801816521 is about 1894.7051586312.

The spelling of 6801816521 in words is "six billion, eight hundred one million, eight hundred sixteen thousand, five hundred twenty-one".