21121102020021 has 16 divisors (see below), whose sum is σ = 28178515359744. Its totient is φ = 14072212216944.

The previous prime is 21121102019987. The next prime is 21121102020023. The reversal of 21121102020021 is 12002020112112.

It is not a de Polignac number, because 21121102020021 - 2¹¹ = 21121102017973 is a prime.

It is a super-2 number, since 2×21121102020021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121102020023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 248186940 + ... + 248272026.

It is an arithmetic number, because the mean of its divisors is an integer number (1761157209984).

Almost surely, 2^{21121102020021} is an apocalyptic number.

It is an amenable number.

21121102020021 is a deficient number, since it is larger than the sum of its proper divisors (7057413339723).

21121102020021 is a wasteful number, since it uses less digits than its factorization.

21121102020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134200.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21121102020021 its reverse (12002020112112), we get a palindrome (33123122132133).

The spelling of 21121102020021 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred two million, twenty thousand, twenty-one".