78123761 has 4 divisors (see below), whose sum is σ = 80235252. Its totient is φ = 76012272.

The previous prime is 78123739. The next prime is 78123827. The reversal of 78123761 is 16732187.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58232161 + 19891600 = 7631^2 + 4460^2 .

It is a cyclic number.

It is not a de Polignac number, because 78123761 - 2⁶ = 78123697 is a prime.

It is a super-2 number, since 2×78123761² = 12206644065570242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78123061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1055690 + ... + 1055763.

It is an arithmetic number, because the mean of its divisors is an integer number (20058813).

Almost surely, 2^78123761 is an apocalyptic number.

It is an amenable number.

78123761 is a deficient number, since it is larger than the sum of its proper divisors (2111491).

78123761 is a wasteful number, since it uses less digits than its factorization.

78123761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2111490.

The product of its digits is 14112, while the sum is 35.

The square root of 78123761 is about 8838.7646761298. The cubic root of 78123761 is about 427.4917267530.

It can be divided in two parts, 781 and 23761, that added together give a palindrome (24542).

The spelling of 78123761 in words is "seventy-eight million, one hundred twenty-three thousand, seven hundred sixty-one".