21813032531 has 2 divisors, whose sum is σ = 21813032532. Its totient is φ = 21813032530.

The previous prime is 21813032513. The next prime is 21813032599. The reversal of 21813032531 is 13523031812.

Together with previous prime (21813032513) 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 21813032531 - 2⁶ = 21813032467 is a prime.

It is a super-2 number, since 2×21813032531² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21813032494 and 21813032503.

It is not a weakly prime, because it can be changed into another prime (21813031531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906516265 + 10906516266.

It is an arithmetic number, because the mean of its divisors is an integer number (10906516266).

Almost surely, 2^21813032531 is an apocalyptic number.

21813032531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21813032531 is an equidigital number, since it uses as much as digits as its factorization.

21813032531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 29.

The spelling of 21813032531 in words is "twenty-one billion, eight hundred thirteen million, thirty-two thousand, five hundred thirty-one".