78121172 has 24 divisors (see below), whose sum is σ = 138738600. Its totient is φ = 38486016.

The previous prime is 78121139. The next prime is 78121187. The reversal of 78121172 is 27112187.

It can be written as a sum of positive squares in 4 ways, for example, as 5973136 + 72148036 = 2444^2 + 8494^2 .

It is a super-2 number, since 2×78121172² = 12205835029307168, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 101204 + ... + 101972.

It is an arithmetic number, because the mean of its divisors is an integer number (5780775).

Almost surely, 2^78121172 is an apocalyptic number.

It is an amenable number.

78121172 is a deficient number, since it is larger than the sum of its proper divisors (60617428).

78121172 is a wasteful number, since it uses less digits than its factorization.

78121172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1115 (or 1113 counting only the distinct ones).

The product of its digits is 1568, while the sum is 29.

The square root of 78121172 is about 8838.6182177985. The cubic root of 78121172 is about 427.4870043813.

The spelling of 78121172 in words is "seventy-eight million, one hundred twenty-one thousand, one hundred seventy-two".