20021120051566 has 32 divisors (see below), whose sum is σ = 31106911904640. Its totient is φ = 9653033193216.

The previous prime is 20021120051551. The next prime is 20021120051657. The reversal of 20021120051566 is 66515002112002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 642036811 + ... + 642067993.

It is an arithmetic number, because the mean of its divisors is an integer number (972090997020).

Almost surely, 2^{20021120051566} is an apocalyptic number.

20021120051566 is a deficient number, since it is larger than the sum of its proper divisors (11085791853074).

20021120051566 is a wasteful number, since it uses less digits than its factorization.

20021120051566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44988.

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 20021120051566 its reverse (66515002112002), we get a palindrome (86536122163568).

The spelling of 20021120051566 in words is "twenty trillion, twenty-one billion, one hundred twenty million, fifty-one thousand, five hundred sixty-six".