21621555634522 has 8 divisors (see below), whose sum is σ = 32448317850900. Its totient is φ = 10805449684224.

The previous prime is 21621555634519. The next prime is 21621555634531. The reversal of 21621555634522 is 22543655512612.

It can be written as a sum of positive squares in 2 ways, for example, as 18724755038521 + 2896800596001 = 4327211^2 + 1701999^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 2664061447 + ... + 2664069562.

Almost surely, 2^{21621555634522} is an apocalyptic number.

21621555634522 is a deficient number, since it is larger than the sum of its proper divisors (10826762216378).

21621555634522 is a wasteful number, since it uses less digits than its factorization.

21621555634522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5328133040.

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

The spelling of 21621555634522 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred fifty-five million, six hundred thirty-four thousand, five hundred twenty-two".