61668538 has 4 divisors (see below), whose sum is σ = 92502810. Its totient is φ = 30834268.

The previous prime is 61668527. The next prime is 61668539. The reversal of 61668538 is 83586616.

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

It can be written as a sum of positive squares in only one way, i.e., 43204329 + 18464209 = 6573^2 + 4297^2 .

It is a junction number, because it is equal to n+sod(n) for n = 61668494 and 61668503.

It is not an unprimeable number, because it can be changed into a prime (61668539) 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 as a sum of consecutive naturals, namely, 15417133 + ... + 15417136.

Almost surely, 2^61668538 is an apocalyptic number.

61668538 is a deficient number, since it is larger than the sum of its proper divisors (30834272).

61668538 is a wasteful number, since it uses less digits than its factorization.

61668538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30834271.

The product of its digits is 207360, while the sum is 43.

The square root of 61668538 is about 7852.9318092035. The cubic root of 61668538 is about 395.0825827439.

The spelling of 61668538 in words is "sixty-one million, six hundred sixty-eight thousand, five hundred thirty-eight".