21003311120021 has 16 divisors (see below), whose sum is σ = 22659974726400. Its totient is φ = 19393496548608.

The previous prime is 21003311119997. The next prime is 21003311120107. The reversal of 21003311120021 is 12002111330012.

It is not a de Polignac number, because 21003311120021 - 2¹⁸ = 21003310857877 is a prime.

It is a super-4 number, since 4×21003311120021⁴ (a number of 54 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003311320021) 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, 12278840 + ... + 13884398.

It is an arithmetic number, because the mean of its divisors is an integer number (1416248420400).

Almost surely, 2^{21003311120021} is an apocalyptic number.

It is an amenable number.

21003311120021 is a deficient number, since it is larger than the sum of its proper divisors (1656663606379).

21003311120021 is a wasteful number, since it uses less digits than its factorization.

21003311120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1620148.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21003311120021 its reverse (12002111330012), we get a palindrome (33005422450033).

The spelling of 21003311120021 in words is "twenty-one trillion, three billion, three hundred eleven million, one hundred twenty thousand, twenty-one".