21010403 has 2 divisors, whose sum is σ = 21010404. Its totient is φ = 21010402.

The previous prime is 21010399. The next prime is 21010411. The reversal of 21010403 is 30401012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21010403 - 2² = 21010399 is a prime.

It is not a weakly prime, because it can be changed into another prime (21010433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505201 + 10505202.

It is an arithmetic number, because the mean of its divisors is an integer number (10505202).

Almost surely, 2^21010403 is an apocalyptic number.

21010403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010403 is an equidigital number, since it uses as much as digits as its factorization.

21010403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21010403 is about 4583.7106147749. The cubic root of 21010403 is about 275.9379674003.

Adding to 21010403 its reverse (30401012), we get a palindrome (51411415).

The spelling of 21010403 in words is "twenty-one million, ten thousand, four hundred three".