91890120 has 128 divisors (see below), whose sum is σ = 317721600. Its totient is φ = 20825856.

The previous prime is 91890119. The next prime is 91890121. The reversal of 91890120 is 2109819.

It is an interprime number because it is at equal distance from previous prime (91890119) and next prime (91890121).

It is a super-2 number, since 2×91890120² = 16887588307228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (91890121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116367 + ... + 117153.

It is an arithmetic number, because the mean of its divisors is an integer number (2482200).

Almost surely, 2^91890120 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 91890120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158860800).

91890120 is an abundant number, since it is smaller than the sum of its proper divisors (225831480).

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

91890120 is a wasteful number, since it uses less digits than its factorization.

91890120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 947 (or 943 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 91890120 is about 9585.9334443757. The cubic root of 91890120 is about 451.2559481827.

Adding to 91890120 its reverse (2109819), we get a palindrome (93999939).

The spelling of 91890120 in words is "ninety-one million, eight hundred ninety thousand, one hundred twenty".