21205444531534 has 16 divisors (see below), whose sum is σ = 32160978820656. Its totient is φ = 10485287596800.

The previous prime is 21205444531519. The next prime is 21205444531553. The reversal of 21205444531534 is 43513544450212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42083557 + ... + 42584464.

It is an arithmetic number, because the mean of its divisors is an integer number (2010061176291).

Almost surely, 2^{21205444531534} is an apocalyptic number.

21205444531534 is a deficient number, since it is larger than the sum of its proper divisors (10955534289122).

21205444531534 is a wasteful number, since it uses less digits than its factorization.

21205444531534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84669411.

The product of its (nonzero) digits is 1152000, while the sum is 43.

Adding to 21205444531534 its reverse (43513544450212), we get a palindrome (64718988981746).

The spelling of 21205444531534 in words is "twenty-one trillion, two hundred five billion, four hundred forty-four million, five hundred thirty-one thousand, five hundred thirty-four".