78518261 has 4 divisors (see below), whose sum is σ = 79624224. Its totient is φ = 77412300.

The previous prime is 78518233. The next prime is 78518273. The reversal of 78518261 is 16281587.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78518261 - 2¹⁴ = 78501877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78518201) 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, 552875 + ... + 553016.

It is an arithmetic number, because the mean of its divisors is an integer number (19906056).

Almost surely, 2^78518261 is an apocalyptic number.

78518261 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

78518261 is a deficient number, since it is larger than the sum of its proper divisors (1105963).

78518261 is a wasteful number, since it uses less digits than its factorization.

78518261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1105962.

The product of its digits is 26880, while the sum is 38.

The square root of 78518261 is about 8861.0530412587. The cubic root of 78518261 is about 428.2100844338.

The spelling of 78518261 in words is "seventy-eight million, five hundred eighteen thousand, two hundred sixty-one".