21785431054 has 16 divisors (see below), whose sum is σ = 33219052416. Its totient is φ = 10712469600.

The previous prime is 21785431039. The next prime is 21785431097. The reversal of 21785431054 is 45013458712.

It is a junction number, because it is equal to n+sod(n) for n = 21785430998 and 21785431016.

It is a congruent number.

It is an unprimeable number.

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, 1197184 + ... + 1215244.

It is an arithmetic number, because the mean of its divisors is an integer number (2076190776).

Almost surely, 2^21785431054 is an apocalyptic number.

21785431054 is a deficient number, since it is larger than the sum of its proper divisors (11433621362).

21785431054 is a wasteful number, since it uses less digits than its factorization.

21785431054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28011.

The product of its (nonzero) digits is 134400, while the sum is 40.

Adding to 21785431054 its reverse (45013458712), we get a palindrome (66798889766).

The spelling of 21785431054 in words is "twenty-one billion, seven hundred eighty-five million, four hundred thirty-one thousand, fifty-four".