21101211121020 has 24 divisors (see below), whose sum is σ = 59083391139024. Its totient is φ = 5626989632256.

The previous prime is 21101211120991. The next prime is 21101211121049. The reversal of 21101211121020 is 2012111210112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21101211120991) and next prime (21101211121049).

It is a super-2 number, since 2×21101211121020² (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 a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175843425949 + ... + 175843426068.

It is an arithmetic number, because the mean of its divisors is an integer number (2461807964126).

Almost surely, 2^{21101211121020} is an apocalyptic number.

21101211121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101211121020 is an abundant number, since it is smaller than the sum of its proper divisors (37982180018004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21101211121020 is a wasteful number, since it uses less digits than its factorization.

21101211121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351686852029 (or 351686852027 counting only the distinct ones).

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

Adding to 21101211121020 its reverse (2012111210112), we get a palindrome (23113322331132).

The spelling of 21101211121020 in words is "twenty-one trillion, one hundred one billion, two hundred eleven million, one hundred twenty-one thousand, twenty".