91001001 has 16 divisors (see below), whose sum is σ = 149335424. Its totient is φ = 48000384.

The previous prime is 91000999. The next prime is 91001059. The reversal of 91001001 is 10010019.

It is not a de Polignac number, because 91001001 - 2¹ = 91000999 is a prime.

91001001 is a modest number, since divided by 1001 gives 91 as remainder.

It is not an unprimeable number, because it can be changed into a prime (91003001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166396 + ... + 166941.

It is an arithmetic number, because the mean of its divisors is an integer number (9333464).

Almost surely, 2^91001001 is an apocalyptic number.

91001001 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

91001001 is a deficient number, since it is larger than the sum of its proper divisors (58334423).

91001001 is a wasteful number, since it uses less digits than its factorization.

91001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333360.

The product of its (nonzero) digits is 9, while the sum is 12.

The square root of 91001001 is about 9539.4444806813. Note that the first 4 decimals coincide. The cubic root of 91001001 is about 449.7957937667.

It can be divided in two parts, 9100 and 1001, that added together give a palindrome (10101).

The spelling of 91001001 in words is "ninety-one million, one thousand, one".