64500021 has 24 divisors (see below), whose sum is σ = 95150016. Its totient is φ = 42094080.

The previous prime is 64500001. The next prime is 64500049. The reversal of 64500021 is 12000546.

It is a happy number.

64500021 is a `hidden beast` number, since 645 + 0 + 0 + 0 + 21 = 666.

64500021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 64500021 - 2¹⁵ = 64467253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 64499967 and 64500003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64500001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123066 + ... + 123588.

It is an arithmetic number, because the mean of its divisors is an integer number (3964584).

Almost surely, 2^64500021 is an apocalyptic number.

It is an amenable number.

64500021 is a deficient number, since it is larger than the sum of its proper divisors (30649995).

64500021 is a wasteful number, since it uses less digits than its factorization.

64500021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 793 (or 790 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 64500021 is about 8031.1905095073. The cubic root of 64500021 is about 401.0390092294.

Adding to 64500021 its reverse (12000546), we get a palindrome (76500567).

The spelling of 64500021 in words is "sixty-four million, five hundred thousand, twenty-one".