21509997676 has 12 divisors (see below), whose sum is σ = 37664689608. Its totient is φ = 10748657792.

The previous prime is 21509997671. The next prime is 21509997727. The reversal of 21509997676 is 67679990512.

It is not an unprimeable number, because it can be changed into a prime (21509997671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1577626 + ... + 1591201.

It is an arithmetic number, because the mean of its divisors is an integer number (3138724134).

Almost surely, 2^21509997676 is an apocalyptic number.

It is an amenable number.

21509997676 is a deficient number, since it is larger than the sum of its proper divisors (16154691932).

21509997676 is a wasteful number, since it uses less digits than its factorization.

21509997676 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3170528 (or 3170526 counting only the distinct ones).

The product of its (nonzero) digits is 12859560, while the sum is 61.

The spelling of 21509997676 in words is "twenty-one billion, five hundred nine million, nine hundred ninety-seven thousand, six hundred seventy-six".