68644421 has 4 divisors (see below), whose sum is σ = 71011500. Its totient is φ = 66277344.

The previous prime is 68644409. The next prime is 68644423. The reversal of 68644421 is 12444686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12444686 = 2 ⋅6222343.

It can be written as a sum of positive squares in 2 ways, for example, as 49547521 + 19096900 = 7039^2 + 4370^2 .

It is a cyclic number.

It is not a de Polignac number, because 68644421 - 2⁶ = 68644357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68644423) 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 3 ways as a sum of consecutive naturals, for example, 1183496 + ... + 1183553.

It is an arithmetic number, because the mean of its divisors is an integer number (17752875).

Almost surely, 2^68644421 is an apocalyptic number.

It is an amenable number.

68644421 is a deficient number, since it is larger than the sum of its proper divisors (2367079).

68644421 is a wasteful number, since it uses less digits than its factorization.

68644421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2367078.

The product of its digits is 36864, while the sum is 35.

The square root of 68644421 is about 8285.1928764513. The cubic root of 68644421 is about 409.4508233269.

The spelling of 68644421 in words is "sixty-eight million, six hundred forty-four thousand, four hundred twenty-one".