21566231650 has 48 divisors (see below), whose sum is σ = 41788262880. Its totient is φ = 8273398400.

The previous prime is 21566231647. The next prime is 21566231651. The reversal of 21566231650 is 5613266512.

It is not an unprimeable number, because it can be changed into a prime (21566231651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31797 + ... + 210103.

It is an arithmetic number, because the mean of its divisors is an integer number (870588810).

Almost surely, 2^21566231650 is an apocalyptic number.

21566231650 is a deficient number, since it is larger than the sum of its proper divisors (20222031230).

21566231650 is a wasteful number, since it uses less digits than its factorization.

21566231650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178419 (or 178414 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 21566231650 in words is "twenty-one billion, five hundred sixty-six million, two hundred thirty-one thousand, six hundred fifty".