61965509 has 2 divisors, whose sum is σ = 61965510. Its totient is φ = 61965508.

The previous prime is 61965503. The next prime is 61965523. The reversal of 61965509 is 90556916.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56776225 + 5189284 = 7535^2 + 2278^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61965509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61965503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30982754 + 30982755.

It is an arithmetic number, because the mean of its divisors is an integer number (30982755).

Almost surely, 2^61965509 is an apocalyptic number.

It is an amenable number.

61965509 is a deficient number, since it is larger than the sum of its proper divisors (1).

61965509 is an equidigital number, since it uses as much as digits as its factorization.

61965509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72900, while the sum is 41.

The square root of 61965509 is about 7871.8173886340. The cubic root of 61965509 is about 395.7157539995.

The spelling of 61965509 in words is "sixty-one million, nine hundred sixty-five thousand, five hundred nine".