21576641644 has 6 divisors (see below), whose sum is σ = 37759122884. Its totient is φ = 10788320820.

The previous prime is 21576641641. The next prime is 21576641651. The reversal of 21576641644 is 44614667512.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21576641594 and 21576641603.

It is not an unprimeable number, because it can be changed into a prime (21576641641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2697080202 + ... + 2697080209.

Almost surely, 2^21576641644 is an apocalyptic number.

It is an amenable number.

21576641644 is a deficient number, since it is larger than the sum of its proper divisors (16182481240).

21576641644 is a wasteful number, since it uses less digits than its factorization.

21576641644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5394160415 (or 5394160413 counting only the distinct ones).

The product of its digits is 967680, while the sum is 46.

The spelling of 21576641644 in words is "twenty-one billion, five hundred seventy-six million, six hundred forty-one thousand, six hundred forty-four".