20001021210105 has 32 divisors (see below), whose sum is σ = 34475025271680. Its totient is φ = 9843305971200.

The previous prime is 20001021210103. The next prime is 20001021210127. The reversal of 20001021210105 is 50101212010002.

It is not a de Polignac number, because 20001021210105 - 2¹ = 20001021210103 is a prime.

It is a super-2 number, since 2×20001021210105² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (20001021210103) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16876596 + ... + 18022805.

It is an arithmetic number, because the mean of its divisors is an integer number (1077344539740).

Almost surely, 2^{20001021210105} is an apocalyptic number.

It is an amenable number.

20001021210105 is a deficient number, since it is larger than the sum of its proper divisors (14474004061575).

20001021210105 is a wasteful number, since it uses less digits than its factorization.

20001021210105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34902361.

The product of its (nonzero) digits is 40, while the sum is 15.

Adding to 20001021210105 its reverse (50101212010002), we get a palindrome (70102233220107).

The spelling of 20001021210105 in words is "twenty trillion, one billion, twenty-one million, two hundred ten thousand, one hundred five".