21051168444 has 72 divisors (see below), whose sum is σ = 53859955968. Its totient is φ = 6932069280.

The previous prime is 21051168409. The next prime is 21051168497. The reversal of 21051168444 is 44486115012.

21051168444 is a `hidden beast` number, since 2 + 1 + 0 + 51 + 168 + 444 = 666.

It is a super-4 number, since 4×21051168444⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21051168399 and 21051168408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1406239 + ... + 1421129.

It is an arithmetic number, because the mean of its divisors is an integer number (748054944).

Almost surely, 2^21051168444 is an apocalyptic number.

It is an amenable number.

21051168444 is an abundant number, since it is smaller than the sum of its proper divisors (32808787524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21051168444 is a wasteful number, since it uses less digits than its factorization.

21051168444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15375 (or 15370 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The spelling of 21051168444 in words is "twenty-one billion, fifty-one million, one hundred sixty-eight thousand, four hundred forty-four".