91421579 has 4 divisors (see below), whose sum is σ = 91759200. Its totient is φ = 91083960.

The previous prime is 91421537. The next prime is 91421581. The reversal of 91421579 is 97512419.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91421579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91421509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168404 + ... + 168945.

It is an arithmetic number, because the mean of its divisors is an integer number (22939800).

Almost surely, 2^91421579 is an apocalyptic number.

91421579 is a deficient number, since it is larger than the sum of its proper divisors (337621).

91421579 is a wasteful number, since it uses less digits than its factorization.

91421579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337620.

The product of its digits is 22680, while the sum is 38.

The square root of 91421579 is about 9561.4632248417. The cubic root of 91421579 is about 450.4876672065.

It can be divided in two parts, 9 and 1421579, that multiplied together give a triangular number (12794211 = T₅₀₅₈).

The spelling of 91421579 in words is "ninety-one million, four hundred twenty-one thousand, five hundred seventy-nine".