21287089065 has 32 divisors (see below), whose sum is σ = 37170297216. Its totient is φ = 10316943360.

The previous prime is 21287089063. The next prime is 21287089079. The reversal of 21287089065 is 56098078212.

It is not a de Polignac number, because 21287089065 - 2¹ = 21287089063 is a prime.

It is a super-2 number, since 2×21287089065² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21287089063) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 417609 + ... + 465801.

It is an arithmetic number, because the mean of its divisors is an integer number (1161571788).

Almost surely, 2^21287089065 is an apocalyptic number.

It is an amenable number.

21287089065 is a deficient number, since it is larger than the sum of its proper divisors (15883208151).

21287089065 is a wasteful number, since it uses less digits than its factorization.

21287089065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50889.

The product of its (nonzero) digits is 483840, while the sum is 48.

The spelling of 21287089065 in words is "twenty-one billion, two hundred eighty-seven million, eighty-nine thousand, sixty-five".