21100201521 has 16 divisors (see below), whose sum is σ = 32160812928. Its totient is φ = 12054211200.

The previous prime is 21100201487. The next prime is 21100201531. The reversal of 21100201521 is 12510200112.

It is not a de Polignac number, because 21100201521 - 2¹⁵ = 21100168753 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21100201521.

It is not an unprimeable number, because it can be changed into a prime (21100201531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40500 + ... + 209381.

It is an arithmetic number, because the mean of its divisors is an integer number (2010050808).

Almost surely, 2^21100201521 is an apocalyptic number.

21100201521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21100201521 is a deficient number, since it is larger than the sum of its proper divisors (11060611407).

21100201521 is a wasteful number, since it uses less digits than its factorization.

21100201521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253912.

The product of its (nonzero) digits is 40, while the sum is 15.

Adding to 21100201521 its reverse (12510200112), we get a palindrome (33610401633).

The spelling of 21100201521 in words is "twenty-one billion, one hundred million, two hundred one thousand, five hundred twenty-one".