21545112434 has 16 divisors (see below), whose sum is σ = 34023369600. Its totient is φ = 10204148304.

The previous prime is 21545112431. The next prime is 21545112443. The reversal of 21545112434 is 43421154512.

It is a self number, because there is not a number n which added to its sum of digits gives 21545112434.

It is not an unprimeable number, because it can be changed into a prime (21545112431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 265124 + ... + 336720.

It is an arithmetic number, because the mean of its divisors is an integer number (2126460600).

Almost surely, 2^21545112434 is an apocalyptic number.

21545112434 is a deficient number, since it is larger than the sum of its proper divisors (12478257166).

21545112434 is a wasteful number, since it uses less digits than its factorization.

21545112434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79537.

The product of its digits is 19200, while the sum is 32.

Adding to 21545112434 its reverse (43421154512), we get a palindrome (64966266946).

The spelling of 21545112434 in words is "twenty-one billion, five hundred forty-five million, one hundred twelve thousand, four hundred thirty-four".