64615821 has 8 divisors (see below), whose sum is σ = 86601600. Its totient is φ = 42853632.

The previous prime is 64615819. The next prime is 64615823. The reversal of 64615821 is 12851646.

It is an interprime number because it is at equal distance from previous prime (64615819) and next prime (64615823).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 64615821 - 2¹ = 64615819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64615823) 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 7 ways as a sum of consecutive naturals, for example, 55221 + ... + 56378.

It is an arithmetic number, because the mean of its divisors is an integer number (10825200).

Almost surely, 2^64615821 is an apocalyptic number.

It is an amenable number.

64615821 is a deficient number, since it is larger than the sum of its proper divisors (21985779).

64615821 is a wasteful number, since it uses less digits than its factorization.

64615821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111795.

The product of its digits is 11520, while the sum is 33.

The square root of 64615821 is about 8038.3966684906. The cubic root of 64615821 is about 401.2788673052.

The spelling of 64615821 in words is "sixty-four million, six hundred fifteen thousand, eight hundred twenty-one".