20521610566 has 16 divisors (see below), whose sum is σ = 31145173920. Its totient is φ = 10140011200.

The previous prime is 20521610561. The next prime is 20521610621. The reversal of 20521610566 is 66501612502.

It is a super-2 number, since 2×20521610566² (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 (20521610561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 308055 + ... + 368701.

It is an arithmetic number, because the mean of its divisors is an integer number (1946573370).

Almost surely, 2^20521610566 is an apocalyptic number.

20521610566 is a deficient number, since it is larger than the sum of its proper divisors (10623563354).

20521610566 is a wasteful number, since it uses less digits than its factorization.

20521610566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62639.

The product of its (nonzero) digits is 21600, while the sum is 34.

The spelling of 20521610566 in words is "twenty billion, five hundred twenty-one million, six hundred ten thousand, five hundred sixty-six".