91221503 has 4 divisors (see below), whose sum is σ = 91247520. Its totient is φ = 91195488.

The previous prime is 91221491. The next prime is 91221509. The reversal of 91221503 is 30512219.

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

It is a cyclic number.

It is not a de Polignac number, because 91221503 - 2¹⁸ = 90959359 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 (91221509) 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, 6743 + ... + 15096.

It is an arithmetic number, because the mean of its divisors is an integer number (22811880).

Almost surely, 2^91221503 is an apocalyptic number.

91221503 is a deficient number, since it is larger than the sum of its proper divisors (26017).

91221503 is a wasteful number, since it uses less digits than its factorization.

91221503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26016.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 91221503 is about 9550.9948696458. The cubic root of 91221503 is about 450.1587966319.

The spelling of 91221503 in words is "ninety-one million, two hundred twenty-one thousand, five hundred three".