21161520161254 has 48 divisors (see below), whose sum is σ = 35168343243264. Its totient is φ = 9542226798720.

The previous prime is 21161520161233. The next prime is 21161520161267. The reversal of 21161520161254 is 45216102516112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 404955792 + ... + 405008044.

It is an arithmetic number, because the mean of its divisors is an integer number (732673817568).

Almost surely, 2^{21161520161254} is an apocalyptic number.

21161520161254 is a deficient number, since it is larger than the sum of its proper divisors (14006823082010).

21161520161254 is a wasteful number, since it uses less digits than its factorization.

21161520161254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65581 (or 65570 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 37.

Adding to 21161520161254 its reverse (45216102516112), we get a palindrome (66377622677366).

The spelling of 21161520161254 in words is "twenty-one trillion, one hundred sixty-one billion, five hundred twenty million, one hundred sixty-one thousand, two hundred fifty-four".