21130033531 has 2 divisors, whose sum is σ = 21130033532. Its totient is φ = 21130033530.

The previous prime is 21130033517. The next prime is 21130033609. The reversal of 21130033531 is 13533003112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21130033531 - 2²³ = 21121644923 is a prime.

It is a super-2 number, since 2×21130033531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21130033501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565016765 + 10565016766.

It is an arithmetic number, because the mean of its divisors is an integer number (10565016766).

Almost surely, 2^21130033531 is an apocalyptic number.

21130033531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130033531 is an equidigital number, since it uses as much as digits as its factorization.

21130033531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810, while the sum is 22.

Adding to 21130033531 its reverse (13533003112), we get a palindrome (34663036643).

The spelling of 21130033531 in words is "twenty-one billion, one hundred thirty million, thirty-three thousand, five hundred thirty-one".