64613821 has 16 divisors (see below), whose sum is σ = 70576704. Its totient is φ = 58915584.

The previous prime is 64613819. The next prime is 64613867. The reversal of 64613821 is 12831646.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 64613821 - 2¹ = 64613819 is a prime.

It is a Duffinian number.

64613821 is a modest number, since divided by 13821 gives 646 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64613881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114486 + ... + 115048.

It is an arithmetic number, because the mean of its divisors is an integer number (4411044).

Almost surely, 2^64613821 is an apocalyptic number.

It is an amenable number.

64613821 is a deficient number, since it is larger than the sum of its proper divisors (5962883).

64613821 is a wasteful number, since it uses less digits than its factorization.

64613821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 780.

The product of its digits is 6912, while the sum is 31.

The square root of 64613821 is about 8038.2722646101. The cubic root of 64613821 is about 401.2747271117.

The spelling of 64613821 in words is "sixty-four million, six hundred thirteen thousand, eight hundred twenty-one".