61978649 has 2 divisors, whose sum is σ = 61978650. Its totient is φ = 61978648.

The previous prime is 61978643. The next prime is 61978687. The reversal of 61978649 is 94687916.

61978649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45657049 + 16321600 = 6757^2 + 4040^2 .

It is a cyclic number.

It is not a de Polignac number, because 61978649 - 2¹⁶ = 61913113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61978597 and 61978606.

It is not a weakly prime, because it can be changed into another prime (61978643) 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 as a sum of consecutive naturals, namely, 30989324 + 30989325.

It is an arithmetic number, because the mean of its divisors is an integer number (30989325).

Almost surely, 2^61978649 is an apocalyptic number.

It is an amenable number.

61978649 is a deficient number, since it is larger than the sum of its proper divisors (1).

61978649 is an equidigital number, since it uses as much as digits as its factorization.

61978649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 50.

The square root of 61978649 is about 7872.6519674123. The cubic root of 61978649 is about 395.7437229863.

The spelling of 61978649 in words is "sixty-one million, nine hundred seventy-eight thousand, six hundred forty-nine".