21000131563 has 2 divisors, whose sum is σ = 21000131564. Its totient is φ = 21000131562.

The previous prime is 21000131519. The next prime is 21000131591. The reversal of 21000131563 is 36513100012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000131563 - 2⁹ = 21000131051 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000131363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500065781 + 10500065782.

It is an arithmetic number, because the mean of its divisors is an integer number (10500065782).

Almost surely, 2^21000131563 is an apocalyptic number.

21000131563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000131563 is an equidigital number, since it uses as much as digits as its factorization.

21000131563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 22.

Adding to 21000131563 its reverse (36513100012), we get a palindrome (57513231575).

The spelling of 21000131563 in words is "twenty-one billion, one hundred thirty-one thousand, five hundred sixty-three".