21137903 has 8 divisors (see below), whose sum is σ = 21605760. Its totient is φ = 20674080.

The previous prime is 21137891. The next prime is 21137911. The reversal of 21137903 is 30973112.

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 21137903 - 2⁴ = 21137887 is a prime.

It is a super-3 number, since 3×21137903³ (a number of 23 digits) contains 333 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 (21137923) 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 7 ways as a sum of consecutive naturals, for example, 11138 + ... + 12896.

It is an arithmetic number, because the mean of its divisors is an integer number (2700720).

Almost surely, 2^21137903 is an apocalyptic number.

21137903 is a deficient number, since it is larger than the sum of its proper divisors (467857).

21137903 is a wasteful number, since it uses less digits than its factorization.

21137903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2017.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 21137903 is about 4597.5975247949. The cubic root of 21137903 is about 276.4950115022.

The spelling of 21137903 in words is "twenty-one million, one hundred thirty-seven thousand, nine hundred three".