61635989 has 2 divisors, whose sum is σ = 61635990. Its totient is φ = 61635988.

The previous prime is 61635983. The next prime is 61636007. The reversal of 61635989 is 98953616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60575089 + 1060900 = 7783^2 + 1030^2 .

It is a cyclic number.

It is not a de Polignac number, because 61635989 - 2⁸ = 61635733 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61635983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30817994 + 30817995.

It is an arithmetic number, because the mean of its divisors is an integer number (30817995).

Almost surely, 2^61635989 is an apocalyptic number.

It is an amenable number.

61635989 is a deficient number, since it is larger than the sum of its proper divisors (1).

61635989 is an equidigital number, since it uses as much as digits as its factorization.

61635989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 47.

The square root of 61635989 is about 7850.8591249621. The cubic root of 61635989 is about 395.0130615774.

The spelling of 61635989 in words is "sixty-one million, six hundred thirty-five thousand, nine hundred eighty-nine".