21099101 has 4 divisors (see below), whose sum is σ = 22209600. Its totient is φ = 19988604.

The previous prime is 21099097. The next prime is 21099103. The reversal of 21099101 is 10199012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21099101 - 2² = 21099097 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21099103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555221 + ... + 555258.

It is an arithmetic number, because the mean of its divisors is an integer number (5552400).

Almost surely, 2^21099101 is an apocalyptic number.

It is an amenable number.

21099101 is a deficient number, since it is larger than the sum of its proper divisors (1110499).

21099101 is a wasteful number, since it uses less digits than its factorization.

21099101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110498.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 21099101 is about 4593.3757738726. The cubic root of 21099101 is about 276.3257242776.

The spelling of 21099101 in words is "twenty-one million, ninety-nine thousand, one hundred one".