91228640 has 48 divisors (see below), whose sum is σ = 217546560. Its totient is φ = 36149760.

The previous prime is 91228639. The next prime is 91228759. The reversal of 91228640 is 4682219.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 91228597 and 91228606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14825 + ... + 20055.

It is an arithmetic number, because the mean of its divisors is an integer number (4532220).

Almost surely, 2^91228640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91228640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108773280).

91228640 is an abundant number, since it is smaller than the sum of its proper divisors (126317920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91228640 is a wasteful number, since it uses less digits than its factorization.

91228640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5355 (or 5347 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 91228640 is about 9551.3684883372. The cubic root of 91228640 is about 450.1705361869.

The spelling of 91228640 in words is "ninety-one million, two hundred twenty-eight thousand, six hundred forty".