21001212201021 has 32 divisors (see below), whose sum is σ = 30438743301120. Its totient is φ = 12802520738304.

The previous prime is 21001212200987. The next prime is 21001212201029. The reversal of 21001212201021 is 12010221210012.

It is not a de Polignac number, because 21001212201021 - 2⁶ = 21001212200957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001212201029) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19467225 + ... + 20517681.

It is an arithmetic number, because the mean of its divisors is an integer number (951210728160).

Almost surely, 2^{21001212201021} is an apocalyptic number.

It is an amenable number.

21001212201021 is a deficient number, since it is larger than the sum of its proper divisors (9437531100099).

21001212201021 is a wasteful number, since it uses less digits than its factorization.

21001212201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055285.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21001212201021 its reverse (12010221210012), we get a palindrome (33011433411033).

The spelling of 21001212201021 in words is "twenty-one trillion, one billion, two hundred twelve million, two hundred one thousand, twenty-one".