21312208793 has 2 divisors, whose sum is σ = 21312208794. Its totient is φ = 21312208792.

The previous prime is 21312208787. The next prime is 21312208807. The reversal of 21312208793 is 39780221312.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21312204169 + 4624 = 145987^2 + 68^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312208793 - 2¹⁶ = 21312143257 is a prime.

It is not a weakly prime, because it can be changed into another prime (21312208993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656104396 + 10656104397.

It is an arithmetic number, because the mean of its divisors is an integer number (10656104397).

Almost surely, 2^21312208793 is an apocalyptic number.

It is an amenable number.

21312208793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312208793 is an equidigital number, since it uses as much as digits as its factorization.

21312208793 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 38.

The spelling of 21312208793 in words is "twenty-one billion, three hundred twelve million, two hundred eight thousand, seven hundred ninety-three".