78510475381 has 4 divisors (see below), whose sum is σ = 84549742732. Its totient is φ = 72471208032.

The previous prime is 78510475297. The next prime is 78510475391. The reversal of 78510475381 is 18357401587.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18357401587 = 7 ⋅2622485941.

It can be written as a sum of positive squares in 2 ways, for example, as 26631302481 + 51879172900 = 163191^2 + 227770^2 .

It is a cyclic number.

It is not a de Polignac number, because 78510475381 - 2¹⁷ = 78510344309 is a prime.

It is a super-2 number, since 2×78510475381² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78510475391) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3019633656 + ... + 3019633681.

It is an arithmetic number, because the mean of its divisors is an integer number (21137435683).

Almost surely, 2^78510475381 is an apocalyptic number.

It is an amenable number.

78510475381 is a deficient number, since it is larger than the sum of its proper divisors (6039267351).

78510475381 is a wasteful number, since it uses less digits than its factorization.

78510475381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6039267350.

The product of its (nonzero) digits is 940800, while the sum is 49.

The spelling of 78510475381 in words is "seventy-eight billion, five hundred ten million, four hundred seventy-five thousand, three hundred eighty-one".