20981327566 has 16 divisors (see below), whose sum is σ = 32625244800. Its totient is φ = 10107757408.

The previous prime is 20981327519. The next prime is 20981327567. The reversal of 20981327566 is 66572318902.

It is a super-2 number, since 2×20981327566² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981327567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 349825 + ... + 405388.

It is an arithmetic number, because the mean of its divisors is an integer number (2039077800).

Almost surely, 2^20981327566 is an apocalyptic number.

20981327566 is a deficient number, since it is larger than the sum of its proper divisors (11643917234).

20981327566 is a wasteful number, since it uses less digits than its factorization.

20981327566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755723.

The product of its (nonzero) digits is 1088640, while the sum is 49.

The spelling of 20981327566 in words is "twenty billion, nine hundred eighty-one million, three hundred twenty-seven thousand, five hundred sixty-six".