91028405 has 16 divisors (see below), whose sum is σ = 120509424. Its totient is φ = 65579520.

The previous prime is 91028383. The next prime is 91028423. The reversal of 91028405 is 50482019.

It can be written as a sum of positive squares in 8 ways, for example, as 14273284 + 76755121 = 3778^2 + 8761^2 .

It is not a de Polignac number, because 91028405 - 2¹⁰ = 91027381 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14414 + ... + 19743.

It is an arithmetic number, because the mean of its divisors is an integer number (7531839).

Almost surely, 2^91028405 is an apocalyptic number.

It is an amenable number.

91028405 is a deficient number, since it is larger than the sum of its proper divisors (29481019).

91028405 is a wasteful number, since it uses less digits than its factorization.

91028405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34216.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 91028405 is about 9540.8807245453. The cubic root of 91028405 is about 449.8409396688.

The spelling of 91028405 in words is "ninety-one million, twenty-eight thousand, four hundred five".