21821231599505 has 16 divisors (see below), whose sum is σ = 28355545165584. Its totient is φ = 16025111850240.

The previous prime is 21821231599493. The next prime is 21821231599507. The reversal of 21821231599505 is 50599513212812.

It can be written as a sum of positive squares in 8 ways, for example, as 15055385536129 + 6765846063376 = 3880127^2 + 2601124^2 .

It is not a de Polignac number, because 21821231599505 - 2¹⁴ = 21821231583121 is a prime.

It is a super-2 number, since 2×21821231599505² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21821231599507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 927367394 + ... + 927390923.

It is an arithmetic number, because the mean of its divisors is an integer number (1772221572849).

Almost surely, 2^{21821231599505} is an apocalyptic number.

It is an amenable number.

21821231599505 is a deficient number, since it is larger than the sum of its proper divisors (6534313566079).

21821231599505 is a wasteful number, since it uses less digits than its factorization.

21821231599505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1854758516.

The product of its (nonzero) digits is 1944000, while the sum is 53.

The spelling of 21821231599505 in words is "twenty-one trillion, eight hundred twenty-one billion, two hundred thirty-one million, five hundred ninety-nine thousand, five hundred five".