91064821 has 4 divisors (see below), whose sum is σ = 91175500. Its totient is φ = 90954144.

The previous prime is 91064819. The next prime is 91064837. The reversal of 91064821 is 12846019.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 27941796 + 63123025 = 5286^2 + 7945^2 .

It is a cyclic number.

It is not a de Polignac number, because 91064821 - 2¹ = 91064819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91064851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54096 + ... + 55753.

It is an arithmetic number, because the mean of its divisors is an integer number (22793875).

Almost surely, 2^91064821 is an apocalyptic number.

It is an amenable number.

91064821 is a deficient number, since it is larger than the sum of its proper divisors (110679).

91064821 is a wasteful number, since it uses less digits than its factorization.

91064821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110678.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 91064821 is about 9542.7889529215. The cubic root of 91064821 is about 449.9009181032.

The spelling of 91064821 in words is "ninety-one million, sixty-four thousand, eight hundred twenty-one".