91222005420 has 648 divisors, whose sum is σ = 367006807440. Its totient is φ = 18228188160.

The previous prime is 91222005419. The next prime is 91222005421. The reversal of 91222005420 is 2450022219.

It is a happy number.

91222005420 is a `hidden beast` number, since 9 + 12 + 220 + 0 + 5 + 420 = 666.

It is an interprime number because it is at equal distance from previous prime (91222005419) and next prime (91222005421).

It is not an unprimeable number, because it can be changed into a prime (91222005421) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 28319410 + ... + 28322630.

It is an arithmetic number, because the mean of its divisors is an integer number (566368530).

Almost surely, 2^91222005420 is an apocalyptic number.

91222005420 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91222005420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183503403720).

91222005420 is an abundant number, since it is smaller than the sum of its proper divisors (275784802020).

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

91222005420 is a wasteful number, since it uses less digits than its factorization.

91222005420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3295 (or 3270 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 91222005420 its reverse (2450022219), we get a palindrome (93672027639).

The spelling of 91222005420 in words is "ninety-one billion, two hundred twenty-two million, five thousand, four hundred twenty".