21011210965 has 4 divisors (see below), whose sum is σ = 25213453164. Its totient is φ = 16808968768.

The previous prime is 21011210963. The next prime is 21011211017. The reversal of 21011210965 is 56901211012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14592156804 + 6419054161 = 120798^2 + 80119^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011210965 - 2¹ = 21011210963 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011210963) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2101121092 + ... + 2101121101.

It is an arithmetic number, because the mean of its divisors is an integer number (6303363291).

Almost surely, 2^21011210965 is an apocalyptic number.

It is an amenable number.

21011210965 is a deficient number, since it is larger than the sum of its proper divisors (4202242199).

21011210965 is an equidigital number, since it uses as much as digits as its factorization.

21011210965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4202242198.

The product of its (nonzero) digits is 1080, while the sum is 28.

Adding to 21011210965 its reverse (56901211012), we get a palindrome (77912421977).

The spelling of 21011210965 in words is "twenty-one billion, eleven million, two hundred ten thousand, nine hundred sixty-five".