642246768409 has 3 divisors (see below), whose sum is σ = 642247569813. Its totient is φ = 642245967006.

The previous prime is 642246768343. The next prime is 642246768431. The reversal of 642246768409 is 904867642246.

The square root of 642246768409 is 801403.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 642246768409 - 2¹⁹ = 642246244121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642246768469) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 400702 + ... + 1202104.

It is an arithmetic number, because the mean of its divisors is an integer number (214082523271).

Almost surely, 2^642246768409 is an apocalyptic number.

642246768409 is the 801403-rd square number.

642246768409 is the 400702-nd centered octagonal number.

It is an amenable number.

642246768409 is a deficient number, since it is larger than the sum of its proper divisors (801404).

642246768409 is an frugal number, since it uses more digits than its factorization.

642246768409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1602806 (or 801403 counting only the distinct ones).

The product of its (nonzero) digits is 27869184, while the sum is 58.

The spelling of 642246768409 in words is "six hundred forty-two billion, two hundred forty-six million, seven hundred sixty-eight thousand, four hundred nine".