21375324247 has 2 divisors, whose sum is σ = 21375324248. Its totient is φ = 21375324246.

The previous prime is 21375324203. The next prime is 21375324277. The reversal of 21375324247 is 74242357312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21375324247 is a prime.

It is a super-2 number, since 2×21375324247² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21375324277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687662123 + 10687662124.

It is an arithmetic number, because the mean of its divisors is an integer number (10687662124).

Almost surely, 2^21375324247 is an apocalyptic number.

21375324247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375324247 is an equidigital number, since it uses as much as digits as its factorization.

21375324247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 40.

The spelling of 21375324247 in words is "twenty-one billion, three hundred seventy-five million, three hundred twenty-four thousand, two hundred forty-seven".