61644409 has 2 divisors, whose sum is σ = 61644410. Its totient is φ = 61644408.

The previous prime is 61644389. The next prime is 61644421. The reversal of 61644409 is 90444616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53071225 + 8573184 = 7285^2 + 2928^2 .

It is a cyclic number.

It is not a de Polignac number, because 61644409 - 2¹³ = 61636217 is a prime.

It is not a weakly prime, because it can be changed into another prime (61644449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30822204 + 30822205.

It is an arithmetic number, because the mean of its divisors is an integer number (30822205).

Almost surely, 2^61644409 is an apocalyptic number.

It is an amenable number.

61644409 is a deficient number, since it is larger than the sum of its proper divisors (1).

61644409 is an equidigital number, since it uses as much as digits as its factorization.

61644409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 61644409 is about 7851.3953536935. The cubic root of 61644409 is about 395.0310481390.

The spelling of 61644409 in words is "sixty-one million, six hundred forty-four thousand, four hundred nine".