8121645065 has 16 divisors (see below), whose sum is σ = 9817848000. Its totient is φ = 6449458752.

The previous prime is 8121645053. The next prime is 8121645067. The reversal of 8121645065 is 5605461218.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 8121645065 - 2⁶ = 8121645001 is a prime.

It is a super-2 number, since 2×8121645065² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (8121645067) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1620854 + ... + 1625856.

It is an arithmetic number, because the mean of its divisors is an integer number (613615500).

Almost surely, 2^8121645065 is an apocalyptic number.

It is an amenable number.

8121645065 is a deficient number, since it is larger than the sum of its proper divisors (1696202935).

8121645065 is a wasteful number, since it uses less digits than its factorization.

8121645065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7336.

The product of its (nonzero) digits is 57600, while the sum is 38.

The square root of 8121645065 is about 90120.1701341048. The cubic root of 8121645065 is about 2010.0861381532.

The spelling of 8121645065 in words is "eight billion, one hundred twenty-one million, six hundred forty-five thousand, sixty-five".