21611235517557 has 8 divisors (see below), whose sum is σ = 32931406502976. Its totient is φ = 12349277438592.

The previous prime is 21611235517549. The next prime is 21611235517559. The reversal of 21611235517557 is 75571553211612.

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

It is not a de Polignac number, because 21611235517557 - 2³ = 21611235517549 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611235517559) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 514553226588 + ... + 514553226629.

It is an arithmetic number, because the mean of its divisors is an integer number (4116425812872).

Almost surely, 2^{21611235517557} is an apocalyptic number.

It is an amenable number.

21611235517557 is a deficient number, since it is larger than the sum of its proper divisors (11320170985419).

21611235517557 is a wasteful number, since it uses less digits than its factorization.

21611235517557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029106453227.

The product of its digits is 2205000, while the sum is 51.

The spelling of 21611235517557 in words is "twenty-one trillion, six hundred eleven billion, two hundred thirty-five million, five hundred seventeen thousand, five hundred fifty-seven".