6561500401 has 2 divisors, whose sum is σ = 6561500402. Its totient is φ = 6561500400.

The previous prime is 6561500383. The next prime is 6561500411. The reversal of 6561500401 is 1040051656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3690684001 + 2870816400 = 60751^2 + 53580^2 .

It is a cyclic number.

It is not a de Polignac number, because 6561500401 - 2¹¹ = 6561498353 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6561500401.

It is not a weakly prime, because it can be changed into another prime (6561500411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280750200 + 3280750201.

It is an arithmetic number, because the mean of its divisors is an integer number (3280750201).

Almost surely, 2^6561500401 is an apocalyptic number.

It is an amenable number.

6561500401 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561500401 is an equidigital number, since it uses as much as digits as its factorization.

6561500401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 6561500401 is about 81003.0888361672. The cubic root of 6561500401 is about 1872.1230333194.

The spelling of 6561500401 in words is "six billion, five hundred sixty-one million, five hundred thousand, four hundred one".