78121843 has 2 divisors, whose sum is σ = 78121844. Its totient is φ = 78121842.

The previous prime is 78121819. The next prime is 78121847. The reversal of 78121843 is 34812187.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78121843 - 2⁵ = 78121811 is a prime.

It is a super-2 number, since 2×78121843² = 12206044707433298, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78121799 and 78121808.

It is not a weakly prime, because it can be changed into another prime (78121847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39060921 + 39060922.

It is an arithmetic number, because the mean of its divisors is an integer number (39060922).

Almost surely, 2^78121843 is an apocalyptic number.

78121843 is a deficient number, since it is larger than the sum of its proper divisors (1).

78121843 is an equidigital number, since it uses as much as digits as its factorization.

78121843 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 78121843 is about 8838.6561761390. The cubic root of 78121843 is about 427.4882283046.

It can be divided in two parts, 7812184 and 3, that added together give a palindrome (7812187).

The spelling of 78121843 in words is "seventy-eight million, one hundred twenty-one thousand, eight hundred forty-three".