91001022720 has 144 divisors (see below), whose sum is σ = 294314415360. Its totient is φ = 23959683072.

The previous prime is 91001022719. The next prime is 91001022743. The reversal of 91001022720 is 2722010019.

It is a super-2 number, since 2×91001022720² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 153372 + ... + 453348.

Almost surely, 2^91001022720 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 91001022720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147157207680).

91001022720 is an abundant number, since it is smaller than the sum of its proper divisors (203313392640).

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

91001022720 is a wasteful number, since it uses less digits than its factorization.

91001022720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300080 (or 300066 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 24.

Adding to 91001022720 its reverse (2722010019), we get a palindrome (93723032739).

The spelling of 91001022720 in words is "ninety-one billion, one million, twenty-two thousand, seven hundred twenty".