21000101220021 has 32 divisors (see below), whose sum is σ = 35218190711808. Its totient is φ = 10812602384640.

The previous prime is 21000101219899. The next prime is 21000101220023. The reversal of 21000101220021 is 12002210100012.

It is not a de Polignac number, because 21000101220021 - 2²¹ = 21000099122869 is a prime.

It is a super-2 number, since 2×21000101220021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21000101219979 and 21000101220006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000101220023) 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, 402228451 + ... + 402280656.

It is an arithmetic number, because the mean of its divisors is an integer number (1100568459744).

Almost surely, 2^{21000101220021} is an apocalyptic number.

21000101220021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21000101220021 is a deficient number, since it is larger than the sum of its proper divisors (14218089491787).

21000101220021 is a wasteful number, since it uses less digits than its factorization.

21000101220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804509241.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000101220021 its reverse (12002210100012), we get a palindrome (33002311320033).

The spelling of 21000101220021 in words is "twenty-one trillion, one hundred one million, two hundred twenty thousand, twenty-one".