61817993 has 2 divisors, whose sum is σ = 61817994. Its totient is φ = 61817992.

The previous prime is 61817989. The next prime is 61818007. The reversal of 61817993 is 39971816.

61817993 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., 61418569 + 399424 = 7837^2 + 632^2 .

It is a cyclic number.

It is not a de Polignac number, because 61817993 - 2² = 61817989 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (61817923) 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, 30908996 + 30908997.

It is an arithmetic number, because the mean of its divisors is an integer number (30908997).

Almost surely, 2^61817993 is an apocalyptic number.

It is an amenable number.

61817993 is a deficient number, since it is larger than the sum of its proper divisors (1).

61817993 is an equidigital number, since it uses as much as digits as its factorization.

61817993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 61817993 is about 7862.4419234739. The cubic root of 61817993 is about 395.4014889092.

The spelling of 61817993 in words is "sixty-one million, eight hundred seventeen thousand, nine hundred ninety-three".