21035332531 has 4 divisors (see below), whose sum is σ = 21548389464. Its totient is φ = 20522275600.

The previous prime is 21035332511. The next prime is 21035332541. The reversal of 21035332531 is 13523353012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21035332531 - 2¹⁵ = 21035299763 is a prime.

It is a super-2 number, since 2×21035332531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21035332531.

It is not an unprimeable number, because it can be changed into a prime (21035332511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256528405 + ... + 256528486.

It is an arithmetic number, because the mean of its divisors is an integer number (5387097366).

Almost surely, 2^21035332531 is an apocalyptic number.

21035332531 is a deficient number, since it is larger than the sum of its proper divisors (513056933).

21035332531 is an equidigital number, since it uses as much as digits as its factorization.

21035332531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513056932.

The product of its (nonzero) digits is 8100, while the sum is 28.

Adding to 21035332531 its reverse (13523353012), we get a palindrome (34558685543).

The spelling of 21035332531 in words is "twenty-one billion, thirty-five million, three hundred thirty-two thousand, five hundred thirty-one".