91393890 has 128 divisors (see below), whose sum is σ = 263208960. Its totient is φ = 19872000.

The previous prime is 91393871. The next prime is 91393903. The reversal of 91393890 is 9839319.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 657441 + ... + 657579.

It is an arithmetic number, because the mean of its divisors is an integer number (2056320).

Almost surely, 2^91393890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91393890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131604480).

91393890 is an abundant number, since it is smaller than the sum of its proper divisors (171815070).

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

91393890 is a wasteful number, since it uses less digits than its factorization.

91393890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 91393890 is about 9560.0151673520. The cubic root of 91393890 is about 450.4421826405.

The spelling of 91393890 in words is "ninety-one million, three hundred ninety-three thousand, eight hundred ninety".