21990232555517 has 8 divisors (see below), whose sum is σ = 23287775713272. Its totient is φ = 20693133849600.

The previous prime is 21990232555451. The next prime is 21990232555549. The reversal of 21990232555517 is 71555523209912.

It can be written as a sum of positive squares in 4 ways, for example, as 14585226921721 + 7405005633796 = 3819061^2 + 2721214^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21990232555517 - 2¹⁴ = 21990232539133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21990282555517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111011084 + ... + 111208997.

It is an arithmetic number, because the mean of its divisors is an integer number (2910971964159).

Almost surely, 2^{21990232555517} is an apocalyptic number.

It is an amenable number.

21990232555517 is a deficient number, since it is larger than the sum of its proper divisors (1297543157755).

21990232555517 is a wasteful number, since it uses less digits than its factorization.

21990232555517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222225919.

The product of its (nonzero) digits is 8505000, while the sum is 56.

The spelling of 21990232555517 in words is "twenty-one trillion, nine hundred ninety billion, two hundred thirty-two million, five hundred fifty-five thousand, five hundred seventeen".