91387929864 has 128 divisors (see below), whose sum is σ = 285285473280. Its totient is φ = 23700460800.

The previous prime is 91387929863. The next prime is 91387929869. The reversal of 91387929864 is 46892978319.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a junction number, because it is equal to n+sod(n) for n = 91387929795 and 91387929804.

It is not an unprimeable number, because it can be changed into a prime (91387929863) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1168879 + ... + 1244609.

It is an arithmetic number, because the mean of its divisors is an integer number (2228792760).

Almost surely, 2^91387929864 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 91387929864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142642736640).

91387929864 is an abundant number, since it is smaller than the sum of its proper divisors (193897543416).

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

91387929864 is a wasteful number, since it uses less digits than its factorization.

91387929864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76411 (or 76407 counting only the distinct ones).

The product of its digits is 47029248, while the sum is 66.

The spelling of 91387929864 in words is "ninety-one billion, three hundred eighty-seven million, nine hundred twenty-nine thousand, eight hundred sixty-four".