21021220010005 has 16 divisors (see below), whose sum is σ = 25276784209920. Its totient is φ = 16782778891648.

The previous prime is 21021220009969. The next prime is 21021220010059. The reversal of 21021220010005 is 50001002212012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21021220010005 - 2²⁵ = 21021186455573 is a prime.

It is a super-2 number, since 2×21021220010005² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9287724 + ... + 11327146.

It is an arithmetic number, because the mean of its divisors is an integer number (1579799013120).

Almost surely, 2^{21021220010005} is an apocalyptic number.

It is an amenable number.

21021220010005 is a deficient number, since it is larger than the sum of its proper divisors (4255564199915).

21021220010005 is a wasteful number, since it uses less digits than its factorization.

21021220010005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2043620.

The product of its (nonzero) digits is 80, while the sum is 16.

Adding to 21021220010005 its reverse (50001002212012), we get a palindrome (71022222222017).

The spelling of 21021220010005 in words is "twenty-one trillion, twenty-one billion, two hundred twenty million, ten thousand, five".