21731103 has 6 divisors (see below), whose sum is σ = 31389384. Its totient is φ = 14487396.

The previous prime is 21731089. The next prime is 21731111. The reversal of 21731103 is 30113712.

It is not a de Polignac number, because 21731103 - 2⁵ = 21731071 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731123) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1207275 + ... + 1207292.

It is an arithmetic number, because the mean of its divisors is an integer number (5231564).

Almost surely, 2^21731103 is an apocalyptic number.

21731103 is a deficient number, since it is larger than the sum of its proper divisors (9658281).

21731103 is a wasteful number, since it uses less digits than its factorization.

21731103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2414573 (or 2414570 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 21731103 is about 4661.6631152412. The cubic root of 21731103 is about 279.0576440804.

Adding to 21731103 its reverse (30113712), we get a palindrome (51844815).

The spelling of 21731103 in words is "twenty-one million, seven hundred thirty-one thousand, one hundred three".