21530505213244 has 12 divisors (see below), whose sum is σ = 38132340558984. Its totient is φ = 10635550767824.

The previous prime is 21530505213227. The next prime is 21530505213253. The reversal of 21530505213244 is 44231250503512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32425459327 + ... + 32425459990.

It is an arithmetic number, because the mean of its divisors is an integer number (3177695046582).

Almost surely, 2^{21530505213244} is an apocalyptic number.

It is an amenable number.

21530505213244 is a deficient number, since it is larger than the sum of its proper divisors (16601835345740).

21530505213244 is a wasteful number, since it uses less digits than its factorization.

21530505213244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64850919404 (or 64850919402 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 37.

Adding to 21530505213244 its reverse (44231250503512), we get a palindrome (65761755716756).

The spelling of 21530505213244 in words is "twenty-one trillion, five hundred thirty billion, five hundred five million, two hundred thirteen thousand, two hundred forty-four".