21333133531 has 2 divisors, whose sum is σ = 21333133532. Its totient is φ = 21333133530.

The previous prime is 21333133513. The next prime is 21333133643. The reversal of 21333133531 is 13533133312.

It is a happy number.

Together with previous prime (21333133513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21333133531 - 2¹¹ = 21333131483 is a prime.

It is a super-2 number, since 2×21333133531² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21333133531.

It is not a weakly prime, because it can be changed into another prime (21333133231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666566765 + 10666566766.

It is an arithmetic number, because the mean of its divisors is an integer number (10666566766).

Almost surely, 2^21333133531 is an apocalyptic number.

21333133531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333133531 is an equidigital number, since it uses as much as digits as its factorization.

21333133531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7290, while the sum is 28.

Adding to 21333133531 its reverse (13533133312), we get a palindrome (34866266843).

The spelling of 21333133531 in words is "twenty-one billion, three hundred thirty-three million, one hundred thirty-three thousand, five hundred thirty-one".