91028398 has 4 divisors (see below), whose sum is σ = 136542600. Its totient is φ = 45514198.

The previous prime is 91028383. The next prime is 91028423. The reversal of 91028398 is 89382019.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89382019 = 61 ⋅1465279.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 91028398.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22757098 + ... + 22757101.

It is an arithmetic number, because the mean of its divisors is an integer number (34135650).

Almost surely, 2^91028398 is an apocalyptic number.

91028398 is a deficient number, since it is larger than the sum of its proper divisors (45514202).

91028398 is a wasteful number, since it uses less digits than its factorization.

91028398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45514201.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 91028398 is about 9540.8803577028. The cubic root of 91028398 is about 449.8409281380.

The spelling of 91028398 in words is "ninety-one million, twenty-eight thousand, three hundred ninety-eight".