64073617921 has 4 divisors (see below), whose sum is σ = 64074136644. Its totient is φ = 64073099200.

The previous prime is 64073617903. The next prime is 64073617961. The reversal of 64073617921 is 12971637046.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 25199975025 + 38873642896 = 158745^2 + 197164^2 .

It is a cyclic number.

It is not a de Polignac number, because 64073617921 - 2⁹ = 64073617409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64073617961) 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 3 ways as a sum of consecutive naturals, for example, 44901 + ... + 360781.

It is an arithmetic number, because the mean of its divisors is an integer number (16018534161).

Almost surely, 2^64073617921 is an apocalyptic number.

It is an amenable number.

64073617921 is a deficient number, since it is larger than the sum of its proper divisors (518723).

64073617921 is a wasteful number, since it uses less digits than its factorization.

64073617921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518722.

The product of its (nonzero) digits is 381024, while the sum is 46.

The spelling of 64073617921 in words is "sixty-four billion, seventy-three million, six hundred seventeen thousand, nine hundred twenty-one".