21637311145 has 8 divisors (see below), whose sum is σ = 25972304904. Its totient is φ = 17304827904.

The previous prime is 21637310977. The next prime is 21637311161. The reversal of 21637311145 is 54111373612.

It can be written as a sum of positive squares in 4 ways, for example, as 1127347776 + 20509963369 = 33576^2 + 143213^2 .

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 21637311145 - 2¹⁷ = 21637180073 is a prime.

It is a super-2 number, since 2×21637311145² (a number of 21 digits) contains 22 as substring.

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 21637311145.

It is an unprimeable number.

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, 608614 + ... + 643183.

It is an arithmetic number, because the mean of its divisors is an integer number (3246538113).

Almost surely, 2^21637311145 is an apocalyptic number.

It is an amenable number.

21637311145 is a deficient number, since it is larger than the sum of its proper divisors (4334993759).

21637311145 is a wasteful number, since it uses less digits than its factorization.

21637311145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255259.

The product of its digits is 15120, while the sum is 34.

Adding to 21637311145 its reverse (54111373612), we get a palindrome (75748684757).

The spelling of 21637311145 in words is "twenty-one billion, six hundred thirty-seven million, three hundred eleven thousand, one hundred forty-five".