21261021531583 has 2 divisors, whose sum is σ = 21261021531584. Its totient is φ = 21261021531582.

The previous prime is 21261021531551. The next prime is 21261021531601. The reversal of 21261021531583 is 38513512016212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21261021531583 - 2⁵ = 21261021531551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21261021531383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630510765791 + 10630510765792.

It is an arithmetic number, because the mean of its divisors is an integer number (10630510765792).

Almost surely, 2^{21261021531583} is an apocalyptic number.

21261021531583 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261021531583 is an equidigital number, since it uses as much as digits as its factorization.

21261021531583 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 86400, while the sum is 40.

Adding to 21261021531583 its reverse (38513512016212), we get a palindrome (59774533547795).

The spelling of 21261021531583 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-one million, five hundred thirty-one thousand, five hundred eighty-three".