21091029091 has 8 divisors (see below), whose sum is σ = 23015092464. Its totient is φ = 19168081920.

The previous prime is 21091029067. The next prime is 21091029103. The reversal of 21091029091 is 19092019012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21091029091 - 2⁹ = 21091028579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21091029031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 239290 + ... + 315343.

It is an arithmetic number, because the mean of its divisors is an integer number (2876886558).

Almost surely, 2^21091029091 is an apocalyptic number.

21091029091 is a deficient number, since it is larger than the sum of its proper divisors (1924063373).

21091029091 is a wasteful number, since it uses less digits than its factorization.

21091029091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558101.

The product of its (nonzero) digits is 2916, while the sum is 34.

The spelling of 21091029091 in words is "twenty-one billion, ninety-one million, twenty-nine thousand, ninety-one".