21304051644 has 48 divisors (see below), whose sum is σ = 52346201600. Its totient is φ = 6724964736.

The previous prime is 21304051627. The next prime is 21304051649. The reversal of 21304051644 is 44615040312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304051649) 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 15 ways as a sum of consecutive naturals, for example, 613992 + ... + 647760.

Almost surely, 2^21304051644 is an apocalyptic number.

It is an amenable number.

21304051644 is an abundant number, since it is smaller than the sum of its proper divisors (31042149956).

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

21304051644 is a wasteful number, since it uses less digits than its factorization.

21304051644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36562 (or 36560 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21304051644 its reverse (44615040312), we get a palindrome (65919091956).

The spelling of 21304051644 in words is "twenty-one billion, three hundred four million, fifty-one thousand, six hundred forty-four".