21455993042 has 8 divisors (see below), whose sum is σ = 35109806832. Its totient is φ = 9752724100.

The previous prime is 21455992981. The next prime is 21455993047. The reversal of 21455993042 is 24039955412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21455992984 and 21455993002.

It is not an unprimeable number, because it can be changed into a prime (21455993047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 487636184 + ... + 487636227.

It is an arithmetic number, because the mean of its divisors is an integer number (4388725854).

Almost surely, 2^21455993042 is an apocalyptic number.

21455993042 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21455993042 is a deficient number, since it is larger than the sum of its proper divisors (13653813790).

21455993042 is a wasteful number, since it uses less digits than its factorization.

21455993042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 975272424.

The product of its (nonzero) digits is 388800, while the sum is 44.

The spelling of 21455993042 in words is "twenty-one billion, four hundred fifty-five million, nine hundred ninety-three thousand, forty-two".