21231503 has 2 divisors, whose sum is σ = 21231504. Its totient is φ = 21231502.

The previous prime is 21231499. The next prime is 21231523. The reversal of 21231503 is 30513212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21231503 - 2² = 21231499 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615751 + 10615752.

It is an arithmetic number, because the mean of its divisors is an integer number (10615752).

Almost surely, 2^21231503 is an apocalyptic number.

21231503 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231503 is an equidigital number, since it uses as much as digits as its factorization.

21231503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21231503 is about 4607.7655105268. The cubic root of 21231503 is about 276.9025231876.

Adding to 21231503 its reverse (30513212), we get a palindrome (51744715).

The spelling of 21231503 in words is "twenty-one million, two hundred thirty-one thousand, five hundred three".