21728103 has 8 divisors (see below), whose sum is σ = 29007216. Its totient is φ = 14467200.

The previous prime is 21728101. The next prime is 21728111. The reversal of 21728103 is 30182712.

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

It is not a de Polignac number, because 21728103 - 2¹ = 21728101 is a prime.

It is a super-2 number, since 2×21728103² = 944220919957218, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21728101) 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, 1468 + ... + 6753.

It is an arithmetic number, because the mean of its divisors is an integer number (3625902).

Almost surely, 2^21728103 is an apocalyptic number.

21728103 is a deficient number, since it is larger than the sum of its proper divisors (7279113).

21728103 is an equidigital number, since it uses as much as digits as its factorization.

21728103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9105.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21728103 is about 4661.3413305614. The cubic root of 21728103 is about 279.0448020960.

The spelling of 21728103 in words is "twenty-one million, seven hundred twenty-eight thousand, one hundred three".