21001022021020 has 96 divisors (see below), whose sum is σ = 45321060980160. Its totient is φ = 8171261829120.

The previous prime is 21001022021003. The next prime is 21001022021123. The reversal of 21001022021020 is 2012022010012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 684569922 + ... + 684600598.

It is an arithmetic number, because the mean of its divisors is an integer number (472094385210).

Almost surely, 2^{21001022021020} is an apocalyptic number.

21001022021020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001022021020 is an abundant number, since it is smaller than the sum of its proper divisors (24320038959140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001022021020 is a wasteful number, since it uses less digits than its factorization.

21001022021020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36823 (or 36821 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21001022021020 its reverse (2012022010012), we get a palindrome (23013044031032).

The spelling of 21001022021020 in words is "twenty-one trillion, one billion, twenty-two million, twenty-one thousand, twenty".