20531257247 has 2 divisors, whose sum is σ = 20531257248. Its totient is φ = 20531257246.

The previous prime is 20531257169. The next prime is 20531257259. The reversal of 20531257247 is 74275213502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20531257247 - 2¹⁰ = 20531256223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20531257247.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20531257297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265628623 + 10265628624.

It is an arithmetic number, because the mean of its divisors is an integer number (10265628624).

Almost surely, 2^20531257247 is an apocalyptic number.

20531257247 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531257247 is an equidigital number, since it uses as much as digits as its factorization.

20531257247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 117600, while the sum is 38.

The spelling of 20531257247 in words is "twenty billion, five hundred thirty-one million, two hundred fifty-seven thousand, two hundred forty-seven".