75427021665 has 32 divisors (see below), whose sum is σ = 134113392000. Its totient is φ = 40221472320.

The previous prime is 75427021633. The next prime is 75427021667. The reversal of 75427021665 is 56612072457.

75427021665 is a `hidden beast` number, since 7 + 5 + 427 + 0 + 216 + 6 + 5 = 666.

It is not a de Polignac number, because 75427021665 - 2⁵ = 75427021633 is a prime.

It is a super-5 number, since 5×75427021665⁵ (a number of 56 digits) contains 55555 as substring. Note that it is a super-d number also for d = 3.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 75427021665.

It is not an unprimeable number, because it can be changed into a prime (75427021667) 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 31 ways as a sum of consecutive naturals, for example, 901011 + ... + 981159.

It is an arithmetic number, because the mean of its divisors is an integer number (4191043500).

Almost surely, 2^75427021665 is an apocalyptic number.

It is an amenable number.

75427021665 is a deficient number, since it is larger than the sum of its proper divisors (58686370335).

75427021665 is a wasteful number, since it uses less digits than its factorization.

75427021665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87134 (or 87128 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 45.

It can be divided in two parts, 7542 and 7021665, that added together give a palindrome (7029207).

The spelling of 75427021665 in words is "seventy-five billion, four hundred twenty-seven million, twenty-one thousand, six hundred sixty-five".