78751478885209 has 27 divisors (see below), whose sum is σ = 88320946166973. Its totient is φ = 70184012711904.

The previous prime is 78751478885179. The next prime is 78751478885341. The reversal of 78751478885209 is 90258887415787.

The square root of 78751478885209 is 8874203.

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 10098190395225 + 68653288489984 = 3177765^2 + 8285728^2 .

It is not a de Polignac number, because 78751478885209 - 2⁷ = 78751478885081 is a prime.

It is a super-2 number, since 2×78751478885209² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78751478885609) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3345562762 + ... + 3345586300.

Almost surely, 2^{78751478885209} is an apocalyptic number.

78751478885209 is the 8874203-rd square number.

78751478885209 is the 4437102-nd centered octagonal number.

It is an amenable number.

78751478885209 is a deficient number, since it is larger than the sum of its proper divisors (9569467281764).

78751478885209 is an frugal number, since it uses more digits than its factorization.

78751478885209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47162 (or 23581 counting only the distinct ones).

The product of its (nonzero) digits is 2528870400, while the sum is 79.

The spelling of 78751478885209 in words is "seventy-eight trillion, seven hundred fifty-one billion, four hundred seventy-eight million, eight hundred eighty-five thousand, two hundred nine".