91980020 has 48 divisors (see below), whose sum is σ = 212139648. Its totient is φ = 33221760.

The previous prime is 91980017. The next prime is 91980023. The reversal of 91980020 is 2008919.

It is an interprime number because it is at equal distance from previous prime (91980017) and next prime (91980023).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91980023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33209 + ... + 35871.

It is an arithmetic number, because the mean of its divisors is an integer number (4419576).

Almost surely, 2^91980020 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 91980020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106069824).

91980020 is an abundant number, since it is smaller than the sum of its proper divisors (120159628).

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

91980020 is a wasteful number, since it uses less digits than its factorization.

91980020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2840 (or 2838 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 91980020 is about 9590.6214605728. The cubic root of 91980020 is about 451.4030611591.

Adding to 91980020 its reverse (2008919), we get a palindrome (93988939).

The spelling of 91980020 in words is "ninety-one million, nine hundred eighty thousand, twenty".