21521042102 has 16 divisors (see below), whose sum is σ = 36897446400. Its totient is φ = 9222245928.

The previous prime is 21521042089. The next prime is 21521042143. The reversal of 21521042102 is 20124012512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45233 + ... + 212339.

It is an arithmetic number, because the mean of its divisors is an integer number (2306090400).

Almost surely, 2^21521042102 is an apocalyptic number.

21521042102 is a deficient number, since it is larger than the sum of its proper divisors (15376404298).

21521042102 is a wasteful number, since it uses less digits than its factorization.

21521042102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176315.

The product of its (nonzero) digits is 320, while the sum is 20.

Adding to 21521042102 its reverse (20124012512), we get a palindrome (41645054614).

The spelling of 21521042102 in words is "twenty-one billion, five hundred twenty-one million, forty-two thousand, one hundred two".