61749409 has 4 divisors (see below), whose sum is σ = 62106516. Its totient is φ = 61392304.

The previous prime is 61749397. The next prime is 61749431. The reversal of 61749409 is 90494716.

It is a happy number.

61749409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 30913600 + 30835809 = 5560^2 + 5553^2 .

It is a cyclic number.

It is not a de Polignac number, because 61749409 - 2²⁵ = 28194977 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61749109) 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 in 3 ways as a sum of consecutive naturals, for example, 178294 + ... + 178639.

It is an arithmetic number, because the mean of its divisors is an integer number (15526629).

Almost surely, 2^61749409 is an apocalyptic number.

It is an amenable number.

61749409 is a deficient number, since it is larger than the sum of its proper divisors (357107).

61749409 is a wasteful number, since it uses less digits than its factorization.

61749409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357106.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 61749409 is about 7858.0792182314. The cubic root of 61749409 is about 395.2552086793.

The spelling of 61749409 in words is "sixty-one million, seven hundred forty-nine thousand, four hundred nine".