21001440312021 has 16 divisors (see below), whose sum is σ = 30437745274944. Its totient is φ = 12803178562944.

The previous prime is 21001440311981. The next prime is 21001440312091. The reversal of 21001440312021 is 12021304410012.

It is not a de Polignac number, because 21001440312021 - 2¹⁰ = 21001440310997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001440312091) 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, 2516343816 + ... + 2516352161.

It is an arithmetic number, because the mean of its divisors is an integer number (1902359079684).

Almost surely, 2^{21001440312021} is an apocalyptic number.

It is an amenable number.

21001440312021 is a deficient number, since it is larger than the sum of its proper divisors (9436304962923).

21001440312021 is a wasteful number, since it uses less digits than its factorization.

21001440312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5032696100.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21001440312021 its reverse (12021304410012), we get a palindrome (33022744722033).

The spelling of 21001440312021 in words is "twenty-one trillion, one billion, four hundred forty million, three hundred twelve thousand, twenty-one".