21027720224052 has 36 divisors (see below), whose sum is σ = 53189985865380. Its totient is φ = 7004416079232.

The previous prime is 21027720223943. The next prime is 21027720224059. The reversal of 21027720224052 is 25042202772012.

21027720224052 is a `hidden beast` number, since 21 + 0 + 27 + 7 + 202 + 2 + 405 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13133115073296 + 7894605150756 = 3623964^2 + 2809734^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21027720223998 and 21027720224016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21027720224059) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 200946777 + ... + 201051392.

Almost surely, 2^{21027720224052} is an apocalyptic number.

It is an amenable number.

21027720224052 is an abundant number, since it is smaller than the sum of its proper divisors (32162265641328).

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

21027720224052 is a wasteful number, since it uses less digits than its factorization.

21027720224052 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401999632 (or 401999627 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 36.

Adding to 21027720224052 its reverse (25042202772012), we get a palindrome (46069922996064).

The spelling of 21027720224052 in words is "twenty-one trillion, twenty-seven billion, seven hundred twenty million, two hundred twenty-four thousand, fifty-two".