21001011010221 has 64 divisors (see below), whose sum is σ = 33607976878080. Its totient is φ = 11514730011840.

The previous prime is 21001011010207. The next prime is 21001011010279. The reversal of 21001011010221 is 12201011010012.

It is not a de Polignac number, because 21001011010221 - 2⁹ = 21001011009709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001011010197 and 21001011010206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001011050221) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7553976 + ... + 9953118.

It is an arithmetic number, because the mean of its divisors is an integer number (525124638720).

Almost surely, 2^{21001011010221} is an apocalyptic number.

It is an amenable number.

21001011010221 is a deficient number, since it is larger than the sum of its proper divisors (12606965867859).

21001011010221 is a wasteful number, since it uses less digits than its factorization.

21001011010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2399806.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21001011010221 its reverse (12201011010012), we get a palindrome (33202022020233).

The spelling of 21001011010221 in words is "twenty-one trillion, one billion, eleven million, ten thousand, two hundred twenty-one".