21343634537517 has 20 divisors (see below), whose sum is σ = 31889976674556. Its totient is φ = 14226288966720.

The previous prime is 21343634537501. The next prime is 21343634537531. The reversal of 21343634537517 is 71573543634312.

21343634537517 is a `hidden beast` number, since 2 + 1 + 3 + 43 + 6 + 34 + 53 + 7 + 517 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14105350092681 + 7238284444836 = 3755709^2 + 2690406^2 .

It is not a de Polignac number, because 21343634537517 - 2⁴ = 21343634537501 is a prime.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343634537317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25518538 + ... + 26341659.

Almost surely, 2^{21343634537517} is an apocalyptic number.

21343634537517 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21343634537517 is a deficient number, since it is larger than the sum of its proper divisors (10546342137039).

21343634537517 is an equidigital number, since it uses as much as digits as its factorization.

21343634537517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51865290 (or 51865281 counting only the distinct ones).

The product of its digits is 19051200, while the sum is 54.

The spelling of 21343634537517 in words is "twenty-one trillion, three hundred forty-three billion, six hundred thirty-four million, five hundred thirty-seven thousand, five hundred seventeen".