61779917 has 2 divisors, whose sum is σ = 61779918. Its totient is φ = 61779916.

The previous prime is 61779911. The next prime is 61779937. The reversal of 61779917 is 71997716.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42367081 + 19412836 = 6509^2 + 4406^2 .

It is a cyclic number.

It is not a de Polignac number, because 61779917 - 2¹⁶ = 61714381 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61779911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30889958 + 30889959.

It is an arithmetic number, because the mean of its divisors is an integer number (30889959).

Almost surely, 2^61779917 is an apocalyptic number.

It is an amenable number.

61779917 is a deficient number, since it is larger than the sum of its proper divisors (1).

61779917 is an equidigital number, since it uses as much as digits as its factorization.

61779917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 166698, while the sum is 47.

The square root of 61779917 is about 7860.0201653685. The cubic root of 61779917 is about 395.3202914106.

The spelling of 61779917 in words is "sixty-one million, seven hundred seventy-nine thousand, nine hundred seventeen".