991121222001001 has 16 divisors (see below), whose sum is σ = 1219960409673600. Its totient is φ = 784107384640128.

The previous prime is 991121222000999. The next prime is 991121222001019. The reversal of 991121222001001 is 100100222121199.

It is a cyclic number.

It is not a de Polignac number, because 991121222001001 - 2¹ = 991121222000999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991121222001101) 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, 529890196 + ... + 531757333.

It is an arithmetic number, because the mean of its divisors is an integer number (76247525604600).

Almost surely, 2^{991121222001001} is an apocalyptic number.

991121222001001 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

991121222001001 is a deficient number, since it is larger than the sum of its proper divisors (228839187672599).

991121222001001 is a wasteful number, since it uses less digits than its factorization.

991121222001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061657808.

The product of its (nonzero) digits is 1296, while the sum is 31.

The spelling of 991121222001001 in words is "nine hundred ninety-one trillion, one hundred twenty-one billion, two hundred twenty-two million, one thousand, one".