21520616534554 has 32 divisors (see below), whose sum is σ = 33392438553600. Its totient is φ = 10395760976640.

The previous prime is 21520616534471. The next prime is 21520616534663. The reversal of 21520616534554 is 45543561602512.

It is a junction number, because it is equal to n+sod(n) for n = 21520616534498 and 21520616534507.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33552292 + ... + 34187680.

It is an arithmetic number, because the mean of its divisors is an integer number (1043513704800).

Almost surely, 2^{21520616534554} is an apocalyptic number.

21520616534554 is a deficient number, since it is larger than the sum of its proper divisors (11871822019046).

21520616534554 is a wasteful number, since it uses less digits than its factorization.

21520616534554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640078.

The product of its (nonzero) digits is 4320000, while the sum is 49.

The spelling of 21520616534554 in words is "twenty-one trillion, five hundred twenty billion, six hundred sixteen million, five hundred thirty-four thousand, five hundred fifty-four".