21020513150021 has 32 divisors (see below), whose sum is σ = 26223294406656. Its totient is φ = 16369685280000.

The previous prime is 21020513149949. The next prime is 21020513150059. The reversal of 21020513150021 is 12005131502012.

It is a cyclic number.

It is not a de Polignac number, because 21020513150021 - 2²² = 21020508955717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020513150071) 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, 1347374621 + ... + 1347390221.

It is an arithmetic number, because the mean of its divisors is an integer number (819477950208).

Almost surely, 2^{21020513150021} is an apocalyptic number.

It is an amenable number.

21020513150021 is a deficient number, since it is larger than the sum of its proper divisors (5202781256635).

21020513150021 is a wasteful number, since it uses less digits than its factorization.

21020513150021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25113.

The product of its (nonzero) digits is 600, while the sum is 23.

Adding to 21020513150021 its reverse (12005131502012), we get a palindrome (33025644652033).

The spelling of 21020513150021 in words is "twenty-one trillion, twenty billion, five hundred thirteen million, one hundred fifty thousand, twenty-one".