78738043609 has 3 divisors (see below), whose sum is σ = 78738324213. Its totient is φ = 78737763006.

The previous prime is 78738043603. The next prime is 78738043613. The reversal of 78738043609 is 90634083787.

The square root of 78738043609 is 280603.

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 78738043609 - 2¹¹ = 78738041561 is a prime.

It is a super-2 number, since 2×78738043609² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78738043609.

It is not an unprimeable number, because it can be changed into a prime (78738043603) 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, 140302 + ... + 420904.

It is an arithmetic number, because the mean of its divisors is an integer number (26246108071).

Almost surely, 2^78738043609 is an apocalyptic number.

78738043609 is the 280603-rd square number.

78738043609 is the 140302-nd centered octagonal number.

It is an amenable number.

78738043609 is a deficient number, since it is larger than the sum of its proper divisors (280604).

78738043609 is an frugal number, since it uses more digits than its factorization.

78738043609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561206 (or 280603 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 55.

The spelling of 78738043609 in words is "seventy-eight billion, seven hundred thirty-eight million, forty-three thousand, six hundred nine".