21500520221354 has 32 divisors (see below), whose sum is σ = 32644432054080. Its totient is φ = 10620080612352.

The previous prime is 21500520221287. The next prime is 21500520221357. The reversal of 21500520221354 is 45312202500512.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21500520221354.

It is not an unprimeable number, because it can be changed into a prime (21500520221357) 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, 31539797 + ... + 32214279.

It is an arithmetic number, because the mean of its divisors is an integer number (1020138501690).

Almost surely, 2^{21500520221354} is an apocalyptic number.

21500520221354 is a deficient number, since it is larger than the sum of its proper divisors (11143911832726).

21500520221354 is a wasteful number, since it uses less digits than its factorization.

21500520221354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675254.

The product of its (nonzero) digits is 24000, while the sum is 32.

Adding to 21500520221354 its reverse (45312202500512), we get a palindrome (66812722721866).

The spelling of 21500520221354 in words is "twenty-one trillion, five hundred billion, five hundred twenty million, two hundred twenty-one thousand, three hundred fifty-four".