21010541555 has 8 divisors (see below), whose sum is σ = 26025961344. Its totient is φ = 16266225600.

The previous prime is 21010541549. The next prime is 21010541579. The reversal of 21010541555 is 55514501012.

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

It is not a de Polignac number, because 21010541555 - 2⁶ = 21010541491 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67775786 + ... + 67776095.

It is an arithmetic number, because the mean of its divisors is an integer number (3253245168).

Almost surely, 2^21010541555 is an apocalyptic number.

21010541555 is a deficient number, since it is larger than the sum of its proper divisors (5015419789).

21010541555 is a wasteful number, since it uses less digits than its factorization.

21010541555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135551917.

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

The spelling of 21010541555 in words is "twenty-one billion, ten million, five hundred forty-one thousand, five hundred fifty-five".