20111221101021 has 16 divisors (see below), whose sum is σ = 27158797338624. Its totient is φ = 13235809990064.

The previous prime is 20111221101007. The next prime is 20111221101043. The reversal of 20111221101021 is 12010112211102.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20111221101021 - 2³⁴ = 20094041231837 is a prime.

It is a super-2 number, since 2×20111221101021² (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 (20111221101061) 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, 30572781 + ... + 31223666.

It is an arithmetic number, because the mean of its divisors is an integer number (1697424833664).

Almost surely, 2^{20111221101021} is an apocalyptic number.

It is an amenable number.

20111221101021 is a deficient number, since it is larger than the sum of its proper divisors (7047576237603).

20111221101021 is a wasteful number, since it uses less digits than its factorization.

20111221101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61797840.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 20111221101021 its reverse (12010112211102), we get a palindrome (32121333312123).

The spelling of 20111221101021 in words is "twenty trillion, one hundred eleven billion, two hundred twenty-one million, one hundred one thousand, twenty-one".