91377780505440 has 576 divisors, whose sum is σ = 343406742110208. Its totient is φ = 20287144120320.

The previous prime is 91377780505423. The next prime is 91377780505447. The reversal of 91377780505440 is 4450508777319.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91377780505447) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 95413609 + ... + 96366551.

It is an arithmetic number, because the mean of its divisors is an integer number (596192260608).

Almost surely, 2^{91377780505440} 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 91377780505440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171703371055104).

91377780505440 is an abundant number, since it is smaller than the sum of its proper divisors (252028961604768).

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

91377780505440 is a wasteful number, since it uses less digits than its factorization.

91377780505440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 953123 (or 953104 counting only the distinct ones).

The product of its (nonzero) digits is 29635200, while the sum is 60.

The spelling of 91377780505440 in words is "ninety-one trillion, three hundred seventy-seven billion, seven hundred eighty million, five hundred five thousand, four hundred forty".