61530290809 has 9 divisors (see below), whose sum is σ = 66630966669. Its totient is φ = 56794214880.

The previous prime is 61530290791. The next prime is 61530290837. The reversal of 61530290809 is 90809203516.

It is a happy number.

The square root of 61530290809 is 248053.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 28779426025 + 32750864784 = 169645^2 + 180972^2 .

It is not a de Polignac number, because 61530290809 - 2¹⁹ = 61529766521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61530293809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3215149 + ... + 3234229.

It is an arithmetic number, because the mean of its divisors is an integer number (7403440741).

Almost surely, 2^61530290809 is an apocalyptic number.

61530290809 is the 248053-rd square number.

61530290809 is the 124027-th centered octagonal number.

It is an amenable number.

61530290809 is a deficient number, since it is larger than the sum of its proper divisors (5100675860).

61530290809 is an frugal number, since it uses more digits than its factorization.

61530290809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38188 (or 19094 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The spelling of 61530290809 in words is "sixty-one billion, five hundred thirty million, two hundred ninety thousand, eight hundred nine".