21812085247 has 2 divisors, whose sum is σ = 21812085248. Its totient is φ = 21812085246.

The previous prime is 21812085241. The next prime is 21812085257. The reversal of 21812085247 is 74258021812.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21812085247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21812085241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906042623 + 10906042624.

It is an arithmetic number, because the mean of its divisors is an integer number (10906042624).

Almost surely, 2^21812085247 is an apocalyptic number.

21812085247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21812085247 is an equidigital number, since it uses as much as digits as its factorization.

21812085247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 71680, while the sum is 40.

The spelling of 21812085247 in words is "twenty-one billion, eight hundred twelve million, eighty-five thousand, two hundred forty-seven".