78280681 has 4 divisors (see below), whose sum is σ = 78306372. Its totient is φ = 78254992.

The previous prime is 78280667. The next prime is 78280687. The reversal of 78280681 is 18608287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18608287 = 47 ⋅395921.

It can be written as a sum of positive squares in 2 ways, for example, as 65464281 + 12816400 = 8091^2 + 3580^2 .

It is a cyclic number.

It is not a de Polignac number, because 78280681 - 2¹¹ = 78278633 is a prime.

It is a super-2 number, since 2×78280681² = 12255730035647522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78280687) 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, 7546 + ... + 14611.

It is an arithmetic number, because the mean of its divisors is an integer number (19576593).

Almost surely, 2^78280681 is an apocalyptic number.

It is an amenable number.

78280681 is a deficient number, since it is larger than the sum of its proper divisors (25691).

78280681 is a wasteful number, since it uses less digits than its factorization.

78280681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25690.

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 78280681 is about 8847.6370291734. The cubic root of 78280681 is about 427.7777564114. Note that the first 4 decimals are identical.

It can be divided in two parts, 78280 and 681, that added together give a square (78961 = 281²).

The spelling of 78280681 in words is "seventy-eight million, two hundred eighty thousand, six hundred eighty-one".