61985857 has 2 divisors, whose sum is σ = 61985858. Its totient is φ = 61985856.

The previous prime is 61985837. The next prime is 61985867. The reversal of 61985857 is 75858916.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40972801 + 21013056 = 6401^2 + 4584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61985857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61985857.

It is not a weakly prime, because it can be changed into another prime (61985827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30992928 + 30992929.

It is an arithmetic number, because the mean of its divisors is an integer number (30992929).

Almost surely, 2^61985857 is an apocalyptic number.

It is an amenable number.

61985857 is a deficient number, since it is larger than the sum of its proper divisors (1).

61985857 is an equidigital number, since it uses as much as digits as its factorization.

61985857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 49.

The square root of 61985857 is about 7873.1097413919. The cubic root of 61985857 is about 395.7590638079.

The spelling of 61985857 in words is "sixty-one million, nine hundred eighty-five thousand, eight hundred fifty-seven".