21506205516014 has 4 divisors (see below), whose sum is σ = 32259308274024. Its totient is φ = 10753102758006.

The previous prime is 21506205516013. The next prime is 21506205516017. The reversal of 21506205516014 is 41061550260512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21506205516013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5376551379002 + ... + 5376551379005.

It is an arithmetic number, because the mean of its divisors is an integer number (8064827068506).

Almost surely, 2^{21506205516014} is an apocalyptic number.

21506205516014 is a deficient number, since it is larger than the sum of its proper divisors (10753102758010).

21506205516014 is a wasteful number, since it uses less digits than its factorization.

21506205516014 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10753102758009.

The product of its (nonzero) digits is 72000, while the sum is 38.

Adding to 21506205516014 its reverse (41061550260512), we get a palindrome (62567755776526).

The spelling of 21506205516014 in words is "twenty-one trillion, five hundred six billion, two hundred five million, five hundred sixteen thousand, fourteen".