21372103 has 2 divisors, whose sum is σ = 21372104. Its totient is φ = 21372102.

The previous prime is 21372089. The next prime is 21372133. The reversal of 21372103 is 30127312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21372103 - 2⁹ = 21371591 is a prime.

It is a super-3 number, since 3×21372103³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21372133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686051 + 10686052.

It is an arithmetic number, because the mean of its divisors is an integer number (10686052).

Almost surely, 2^21372103 is an apocalyptic number.

21372103 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372103 is an equidigital number, since it uses as much as digits as its factorization.

21372103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21372103 is about 4622.9971879723. The cubic root of 21372103 is about 277.5124167266.

Adding to 21372103 its reverse (30127312), we get a palindrome (51499415).

The spelling of 21372103 in words is "twenty-one million, three hundred seventy-two thousand, one hundred three".