21506053206031 has 2 divisors, whose sum is σ = 21506053206032. Its totient is φ = 21506053206030.

The previous prime is 21506053206013. The next prime is 21506053206047. The reversal of 21506053206031 is 13060235060512.

Together with previous prime (21506053206013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21506053206031 - 2⁵ = 21506053205999 is a prime.

It is a super-2 number, since 2×21506053206031² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21506053206091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10753026603015 + 10753026603016.

It is an arithmetic number, because the mean of its divisors is an integer number (10753026603016).

Almost surely, 2^{21506053206031} is an apocalyptic number.

21506053206031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21506053206031 is an equidigital number, since it uses as much as digits as its factorization.

21506053206031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32400, while the sum is 34.

Adding to 21506053206031 its reverse (13060235060512), we get a palindrome (34566288266543).

The spelling of 21506053206031 in words is "twenty-one trillion, five hundred six billion, fifty-three million, two hundred six thousand, thirty-one".