21155442404 has 12 divisors (see below), whose sum is σ = 37110385200. Its totient is φ = 10552475208.

The previous prime is 21155442361. The next prime is 21155442421. The reversal of 21155442404 is 40424455112.

It is a super-2 number, since 2×21155442404² (a number of 21 digits) contains 22 as substring.

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, 6309614 + ... + 6312965.

It is an arithmetic number, because the mean of its divisors is an integer number (3092532100).

Almost surely, 2^21155442404 is an apocalyptic number.

It is an amenable number.

21155442404 is a deficient number, since it is larger than the sum of its proper divisors (15954942796).

21155442404 is a wasteful number, since it uses less digits than its factorization.

21155442404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12623002 (or 12623000 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 32.

Adding to 21155442404 its reverse (40424455112), we get a palindrome (61579897516).

The spelling of 21155442404 in words is "twenty-one billion, one hundred fifty-five million, four hundred forty-two thousand, four hundred four".