21050511554 has 8 divisors (see below), whose sum is σ = 31624124220. Its totient is φ = 10509136816.

The previous prime is 21050511541. The next prime is 21050511563. The reversal of 21050511554 is 45511505012.

It can be written as a sum of positive squares in 2 ways, for example, as 20682754225 + 367757329 = 143815^2 + 19177^2 .

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8057849 + ... + 8060460.

Almost surely, 2^21050511554 is an apocalyptic number.

21050511554 is a deficient number, since it is larger than the sum of its proper divisors (10573612666).

21050511554 is a wasteful number, since it uses less digits than its factorization.

21050511554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16118964.

The product of its (nonzero) digits is 5000, while the sum is 29.

The spelling of 21050511554 in words is "twenty-one billion, fifty million, five hundred eleven thousand, five hundred fifty-four".