91124987 has 4 divisors (see below), whose sum is σ = 91684200. Its totient is φ = 90565776.

The previous prime is 91124983. The next prime is 91125017. The reversal of 91124987 is 78942119.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91124987 - 2² = 91124983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91124983) 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, 279362 + ... + 279687.

It is an arithmetic number, because the mean of its divisors is an integer number (22921050).

Almost surely, 2^91124987 is an apocalyptic number.

91124987 is a deficient number, since it is larger than the sum of its proper divisors (559213).

91124987 is a wasteful number, since it uses less digits than its factorization.

91124987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559212.

The product of its digits is 36288, while the sum is 41.

The square root of 91124987 is about 9545.9408651007. The cubic root of 91124987 is about 449.9999786008. Note that the first 4 decimals are identical.

The spelling of 91124987 in words is "ninety-one million, one hundred twenty-four thousand, nine hundred eighty-seven".