91821885 has 16 divisors (see below), whose sum is σ = 147096960. Its totient is φ = 48911040.

The previous prime is 91821869. The next prime is 91821893. The reversal of 91821885 is 58812819.

It is not a de Polignac number, because 91821885 - 2⁴ = 91821869 is a prime.

It is a Curzon number.

It is a congruent number.

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, 10455 + ... + 17115.

It is an arithmetic number, because the mean of its divisors is an integer number (9193560).

Almost surely, 2^91821885 is an apocalyptic number.

It is an amenable number.

91821885 is a deficient number, since it is larger than the sum of its proper divisors (55275075).

91821885 is a wasteful number, since it uses less digits than its factorization.

91821885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7588.

The product of its digits is 46080, while the sum is 42.

The square root of 91821885 is about 9582.3736620944. The cubic root of 91821885 is about 451.1442238958.

The spelling of 91821885 in words is "ninety-one million, eight hundred twenty-one thousand, eight hundred eighty-five".