21403103210021 has 8 divisors (see below), whose sum is σ = 23196307841784. Its totient is φ = 19630871732160.

The previous prime is 21403103209981. The next prime is 21403103210039. The reversal of 21403103210021 is 12001230130412.

It can be written as a sum of positive squares in 4 ways, for example, as 264129184225 + 21138974025796 = 513935^2 + 4597714^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21403103210021 - 2³⁸ = 21128225303077 is a prime.

It is a super-2 number, since 2×21403103210021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21403103209975 and 21403103210002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403103110021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5243286350 + ... + 5243290431.

It is an arithmetic number, because the mean of its divisors is an integer number (2899538480223).

Almost surely, 2^{21403103210021} is an apocalyptic number.

It is an amenable number.

21403103210021 is a deficient number, since it is larger than the sum of its proper divisors (1793204631763).

21403103210021 is a wasteful number, since it uses less digits than its factorization.

21403103210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10486576951.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21403103210021 its reverse (12001230130412), we get a palindrome (33404333340433).

The spelling of 21403103210021 in words is "twenty-one trillion, four hundred three billion, one hundred three million, two hundred ten thousand, twenty-one".