91431280 has 20 divisors (see below), whose sum is σ = 212577912. Its totient is φ = 36572480.

The previous prime is 91431257. The next prime is 91431283. The reversal of 91431280 is 8213419.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91431283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 571366 + ... + 571525.

Almost surely, 2^91431280 is an apocalyptic number.

It is an amenable number.

91431280 is an abundant number, since it is smaller than the sum of its proper divisors (121146632).

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

91431280 is a wasteful number, since it uses less digits than its factorization.

91431280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1142904 (or 1142898 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 91431280 is about 9561.9705082164. The cubic root of 91431280 is about 450.5036008126.

Adding to 91431280 its reverse (8213419), we get a palindrome (99644699).

The spelling of 91431280 in words is "ninety-one million, four hundred thirty-one thousand, two hundred eighty".