609138821 has 2 divisors, whose sum is σ = 609138822. Its totient is φ = 609138820.

The previous prime is 609138811. The next prime is 609138889. The reversal of 609138821 is 128831906.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 331749796 + 277389025 = 18214^2 + 16655^2 .

It is a cyclic number.

It is not a de Polignac number, because 609138821 - 2²² = 604944517 is a prime.

It is equal to p_31776842 and since 609138821 and 31776842 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (609138811) 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 as a sum of consecutive naturals, namely, 304569410 + 304569411.

It is an arithmetic number, because the mean of its divisors is an integer number (304569411).

Almost surely, 2^609138821 is an apocalyptic number.

It is an amenable number.

609138821 is a deficient number, since it is larger than the sum of its proper divisors (1).

609138821 is an equidigital number, since it uses as much as digits as its factorization.

609138821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 609138821 is about 24680.7378536380. The cubic root of 609138821 is about 847.6933173110.

The spelling of 609138821 in words is "six hundred nine million, one hundred thirty-eight thousand, eight hundred twenty-one".