78722261 has 4 divisors (see below), whose sum is σ = 82144992. Its totient is φ = 75299532.

The previous prime is 78722249. The next prime is 78722279. The reversal of 78722261 is 16222787.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16222787 = 7 ⋅2317541.

It is a cyclic number.

It is not a de Polignac number, because 78722261 - 2⁶ = 78722197 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 (78722221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1711331 + ... + 1711376.

It is an arithmetic number, because the mean of its divisors is an integer number (20536248).

Almost surely, 2^78722261 is an apocalyptic number.

It is an amenable number.

78722261 is a deficient number, since it is larger than the sum of its proper divisors (3422731).

78722261 is a wasteful number, since it uses less digits than its factorization.

78722261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3422730.

The product of its digits is 18816, while the sum is 35.

The square root of 78722261 is about 8872.5566214029. The cubic root of 78722261 is about 428.5806110361.

The spelling of 78722261 in words is "seventy-eight million, seven hundred twenty-two thousand, two hundred sixty-one".