623978161 has 4 divisors (see below), whose sum is σ = 626567524. Its totient is φ = 621388800.

The previous prime is 623978153. The next prime is 623978189. The reversal of 623978161 is 161879326.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 349877025 + 274101136 = 18705^2 + 16556^2 .

It is a cyclic number.

It is not a de Polignac number, because 623978161 - 2³ = 623978153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (623978111) 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, 1294320 + ... + 1294801.

It is an arithmetic number, because the mean of its divisors is an integer number (156641881).

Almost surely, 2^623978161 is an apocalyptic number.

It is an amenable number.

623978161 is a deficient number, since it is larger than the sum of its proper divisors (2589363).

623978161 is a wasteful number, since it uses less digits than its factorization.

623978161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2589362.

The product of its digits is 108864, while the sum is 43.

The square root of 623978161 is about 24979.5548599249. The cubic root of 623978161 is about 854.5217671428.

The spelling of 623978161 in words is "six hundred twenty-three million, nine hundred seventy-eight thousand, one hundred sixty-one".