91000001001 has 32 divisors (see below), whose sum is σ = 154482773760. Its totient is φ = 46344824064.

The previous prime is 91000000991. The next prime is 91000001017. The reversal of 91000001001 is 10010000019.

It is not a de Polignac number, because 91000001001 - 2⁶ = 91000000937 is a prime.

91000001001 is a modest number, since divided by 1001 gives 910 as remainder.

It is not an unprimeable number, because it can be changed into a prime (91000001051) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5739210 + ... + 5755043.

It is an arithmetic number, because the mean of its divisors is an integer number (4827586680).

Almost surely, 2^91000001001 is an apocalyptic number.

91000001001 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

91000001001 is a deficient number, since it is larger than the sum of its proper divisors (63482772759).

91000001001 is a wasteful number, since it uses less digits than its factorization.

91000001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11494305.

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

The spelling of 91000001001 in words is "ninety-one billion, one thousand, one".