21352051521 has 16 divisors (see below), whose sum is σ = 31733744320. Its totient is φ = 14189217120.

The previous prime is 21352051519. The next prime is 21352051547. The reversal of 21352051521 is 12515025312.

21352051521 is a `hidden beast` number, since 2 + 135 + 2 + 0 + 5 + 1 + 521 = 666.

It is not a de Polignac number, because 21352051521 - 2¹ = 21352051519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21352051621) 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, 1254835 + ... + 1271736.

It is an arithmetic number, because the mean of its divisors is an integer number (1983359020).

Almost surely, 2^21352051521 is an apocalyptic number.

It is an amenable number.

21352051521 is a deficient number, since it is larger than the sum of its proper divisors (10381692799).

21352051521 is a wasteful number, since it uses less digits than its factorization.

21352051521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2526893 (or 2526887 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

Adding to 21352051521 its reverse (12515025312), we get a palindrome (33867076833).

The spelling of 21352051521 in words is "twenty-one billion, three hundred fifty-two million, fifty-one thousand, five hundred twenty-one".