21350040644 has 24 divisors (see below), whose sum is σ = 37778307840. Its totient is φ = 10556529984.

The previous prime is 21350040637. The next prime is 21350040653. The reversal of 21350040644 is 44604005312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260192 + ... + 332264.

It is an arithmetic number, because the mean of its divisors is an integer number (1574096160).

Almost surely, 2^21350040644 is an apocalyptic number.

It is an amenable number.

21350040644 is a deficient number, since it is larger than the sum of its proper divisors (16428267196).

21350040644 is a wasteful number, since it uses less digits than its factorization.

21350040644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72899 (or 72897 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

Adding to 21350040644 its reverse (44604005312), we get a palindrome (65954045956).

The spelling of 21350040644 in words is "twenty-one billion, three hundred fifty million, forty thousand, six hundred forty-four".