21991103 has 8 divisors (see below), whose sum is σ = 22672848. Its totient is φ = 21317184.

The previous prime is 21991091. The next prime is 21991117. The reversal of 21991103 is 30119912.

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 21991103 - 2¹⁰ = 21990079 is a prime.

It is a super-2 number, since 2×21991103² = 967217222313218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21991163) 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, 4025 + ... + 7757.

It is an arithmetic number, because the mean of its divisors is an integer number (2834106).

Almost surely, 2^21991103 is an apocalyptic number.

21991103 is a deficient number, since it is larger than the sum of its proper divisors (681745).

21991103 is a wasteful number, since it uses less digits than its factorization.

21991103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3913.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 21991103 is about 4689.4672405296. The cubic root of 21991103 is about 280.1661556333.

The spelling of 21991103 in words is "twenty-one million, nine hundred ninety-one thousand, one hundred three".