21012312947 has 2 divisors, whose sum is σ = 21012312948. Its totient is φ = 21012312946.

The previous prime is 21012312869. The next prime is 21012313031. The reversal of 21012312947 is 74921321012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21012312947 - 2¹⁰ = 21012311923 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012317947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506156473 + 10506156474.

It is an arithmetic number, because the mean of its divisors is an integer number (10506156474).

Almost surely, 2^21012312947 is an apocalyptic number.

21012312947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012312947 is an equidigital number, since it uses as much as digits as its factorization.

21012312947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

Adding to 21012312947 its reverse (74921321012), we get a palindrome (95933633959).

The spelling of 21012312947 in words is "twenty-one billion, twelve million, three hundred twelve thousand, nine hundred forty-seven".