21091101 has 8 divisors (see below), whose sum is σ = 29775744. Its totient is φ = 13233600.

The previous prime is 21091079. The next prime is 21091139. The reversal of 21091101 is 10119012.

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

It is not a de Polignac number, because 21091101 - 2¹⁷ = 20960029 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21091151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206725 + ... + 206826.

It is an arithmetic number, because the mean of its divisors is an integer number (3721968).

Almost surely, 2^21091101 is an apocalyptic number.

It is an amenable number.

21091101 is a deficient number, since it is larger than the sum of its proper divisors (8684643).

21091101 is a wasteful number, since it uses less digits than its factorization.

21091101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413571.

The product of its (nonzero) digits is 18, while the sum is 15.

The square root of 21091101 is about 4592.5048720714. The cubic root of 21091101 is about 276.2907956923.

The spelling of 21091101 in words is "twenty-one million, ninety-one thousand, one hundred one".