21012312403 has 2 divisors, whose sum is σ = 21012312404. Its totient is φ = 21012312402.

The previous prime is 21012312379. The next prime is 21012312407. The reversal of 21012312403 is 30421321012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21012312403 - 2²⁹ = 20475441491 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012312407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506156201 + 10506156202.

It is an arithmetic number, because the mean of its divisors is an integer number (10506156202).

Almost surely, 2^21012312403 is an apocalyptic number.

21012312403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012312403 is an equidigital number, since it uses as much as digits as its factorization.

21012312403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21012312403 its reverse (30421321012), we get a palindrome (51433633415).

The spelling of 21012312403 in words is "twenty-one billion, twelve million, three hundred twelve thousand, four hundred three".