91566001421 has 2 divisors, whose sum is σ = 91566001422. Its totient is φ = 91566001420.

The previous prime is 91566001403. The next prime is 91566001433. The reversal of 91566001421 is 12410066519.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 88211970025 + 3354031396 = 297005^2 + 57914^2 .

It is an emirp because it is prime and its reverse (12410066519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91566001421 - 2⁶ = 91566001357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91566001481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45783000710 + 45783000711.

It is an arithmetic number, because the mean of its divisors is an integer number (45783000711).

Almost surely, 2^91566001421 is an apocalyptic number.

It is an amenable number.

91566001421 is a deficient number, since it is larger than the sum of its proper divisors (1).

91566001421 is an equidigital number, since it uses as much as digits as its factorization.

91566001421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 35.

The spelling of 91566001421 in words is "ninety-one billion, five hundred sixty-six million, one thousand, four hundred twenty-one".