91020930 has 192 divisors, whose sum is σ = 299230848. Its totient is φ = 17418240.

The previous prime is 91020911. The next prime is 91020931. The reversal of 91020930 is 3902019.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 91020930.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91020931) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 209994 + ... + 210426.

It is an arithmetic number, because the mean of its divisors is an integer number (1558494).

Almost surely, 2^91020930 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91020930, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149615424).

91020930 is an abundant number, since it is smaller than the sum of its proper divisors (208209918).

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

91020930 is a wasteful number, since it uses less digits than its factorization.

91020930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 91020930 is about 9540.4889811791. The cubic root of 91020930 is about 449.8286261018.

Adding to 91020930 its reverse (3902019), we get a palindrome (94922949).

The spelling of 91020930 in words is "ninety-one million, twenty thousand, nine hundred thirty".