61978665 has 64 divisors (see below), whose sum is σ = 122019840. Its totient is φ = 26231040.

The previous prime is 61978649. The next prime is 61978687. The reversal of 61978665 is 56687916.

61978665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61978665 - 2⁴ = 61978649 is a prime.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 93435 + ... + 94095.

It is an arithmetic number, because the mean of its divisors is an integer number (1906560).

Almost surely, 2^61978665 is an apocalyptic number.

It is an amenable number.

61978665 is a deficient number, since it is larger than the sum of its proper divisors (60041175).

61978665 is a wasteful number, since it uses less digits than its factorization.

61978665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 742.

The product of its digits is 544320, while the sum is 48.

The square root of 61978665 is about 7872.6529835882. The cubic root of 61978665 is about 395.7437570405.

The spelling of 61978665 in words is "sixty-one million, nine hundred seventy-eight thousand, six hundred sixty-five".