91204020 has 36 divisors (see below), whose sum is σ = 276652740. Its totient is φ = 24321024.

The previous prime is 91204013. The next prime is 91204021. The reversal of 91204020 is 2040219.

It can be written as a sum of positive squares in 2 ways, for example, as 24029604 + 67174416 = 4902^2 + 8196^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 91203984 and 91204002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91204021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 253165 + ... + 253524.

Almost surely, 2^91204020 is an apocalyptic number.

91204020 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

91204020 is an abundant number, since it is smaller than the sum of its proper divisors (185448720).

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

91204020 is a wasteful number, since it uses less digits than its factorization.

91204020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506704 (or 506699 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 91204020 is about 9550.0795808203. The cubic root of 91204020 is about 450.1300364938.

Adding to 91204020 its reverse (2040219), we get a palindrome (93244239).

The spelling of 91204020 in words is "ninety-one million, two hundred four thousand, twenty".