21161136465 has 64 divisors (see below), whose sum is σ = 43038604800. Its totient is φ = 9663639552.

The previous prime is 21161136463. The next prime is 21161136467. The reversal of 21161136465 is 56463116112.

21161136465 is a `hidden beast` number, since 2 + 1 + 1 + 6 + 1 + 1 + 3 + 646 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (21161136463) and next prime (21161136467).

It is not a de Polignac number, because 21161136465 - 2¹ = 21161136463 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21161136463) 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 63 ways as a sum of consecutive naturals, for example, 942409 + ... + 964601.

It is an arithmetic number, because the mean of its divisors is an integer number (672478200).

Almost surely, 2^21161136465 is an apocalyptic number.

It is an amenable number.

21161136465 is an abundant number, since it is smaller than the sum of its proper divisors (21877468335).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21161136465 is a wasteful number, since it uses less digits than its factorization.

21161136465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23223 (or 23217 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The spelling of 21161136465 in words is "twenty-one billion, one hundred sixty-one million, one hundred thirty-six thousand, four hundred sixty-five".