91205857242 has 96 divisors (see below), whose sum is σ = 219041521920.
Its totient is φ = 27280872960.
The previous prime is 91205857229. The next prime is 91205857247. The reversal of 91205857242 is 24275850219.
91205857242 is a `hidden beast` number, since 9 + 1 + 20 + 58 + 572 + 4 + 2 = 666.
It is not an unprimeable number, because it can be changed into a prime (91205857247) by changing a digit.
It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2167984 + ... + 2209652.
It is an arithmetic number, because the mean of its divisors is an integer number (2281682520).
Almost surely, 291205857242 is an apocalyptic number.
It is a practical number, because each smaller number is the sum of distinct divisors of 91205857242, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109520760960).
91205857242 is an abundant number, since it is smaller than the sum of its proper divisors (127835664678).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
91205857242 is a wasteful number, since it uses less digits than its factorization.
91205857242 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 42028 (or 42025 counting only the distinct ones).
The product of its (nonzero) digits is 403200, while the sum is 45.
The spelling of 91205857242 in words is "ninety-one billion, two hundred five million, eight hundred fifty-seven thousand, two hundred forty-two".