78181261 has 4 divisors (see below), whose sum is σ = 78264252. Its totient is φ = 78098272.

The previous prime is 78181253. The next prime is 78181273. The reversal of 78181261 is 16218187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16218187 = 17 ⋅954011.

It can be written as a sum of positive squares in 2 ways, for example, as 10118761 + 68062500 = 3181^2 + 8250^2 .

It is a cyclic number.

It is not a de Polignac number, because 78181261 - 2³ = 78181253 is a prime.

It is a super-2 number, since 2×78181261² = 12224619143100242, which contains 22 as substring.

It is a pancake number, because a pancake can be divided into 78181261 parts by 12504 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78181291) 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, 40066 + ... + 41971.

It is an arithmetic number, because the mean of its divisors is an integer number (19566063).

Almost surely, 2^78181261 is an apocalyptic number.

It is an amenable number.

78181261 is a deficient number, since it is larger than the sum of its proper divisors (82991).

78181261 is an equidigital number, since it uses as much as digits as its factorization.

78181261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82990.

The product of its digits is 5376, while the sum is 34.

The square root of 78181261 is about 8842.0167948268. The cubic root of 78181261 is about 427.5965806663.

The spelling of 78181261 in words is "seventy-eight million, one hundred eighty-one thousand, two hundred sixty-one".