21012262405 has 8 divisors (see below), whose sum is σ = 25829708184. Its totient is φ = 16399814400.

The previous prime is 21012262379. The next prime is 21012262409. The reversal of 21012262405 is 50426221012.

It can be written as a sum of positive squares in 4 ways, for example, as 54199044 + 20958063361 = 7362^2 + 144769^2 .

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

It is not a de Polignac number, because 21012262405 - 2⁵ = 21012262373 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21012262405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012262409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51249216 + ... + 51249625.

It is an arithmetic number, because the mean of its divisors is an integer number (3228713523).

Almost surely, 2^21012262405 is an apocalyptic number.

It is an amenable number.

21012262405 is a deficient number, since it is larger than the sum of its proper divisors (4817445779).

21012262405 is a wasteful number, since it uses less digits than its factorization.

21012262405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102498887.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21012262405 its reverse (50426221012), we get a palindrome (71438483417).

The spelling of 21012262405 in words is "twenty-one billion, twelve million, two hundred sixty-two thousand, four hundred five".