78121874 has 16 divisors (see below), whose sum is σ = 120600600. Its totient is φ = 37926144.

The previous prime is 78121873. The next prime is 78121903. The reversal of 78121874 is 47812187.

It can be written as a sum of positive squares in 4 ways, for example, as 58629649 + 19492225 = 7657^2 + 4415^2 .

It is a super-2 number, since 2×78121874² = 12206054394543752, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78121873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51722 + ... + 53210.

Almost surely, 2^78121874 is an apocalyptic number.

78121874 is a gapful number since it is divisible by the number (74) formed by its first and last digit.

78121874 is a deficient number, since it is larger than the sum of its proper divisors (42478726).

78121874 is a wasteful number, since it uses less digits than its factorization.

78121874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2237.

The product of its digits is 25088, while the sum is 38.

The square root of 78121874 is about 8838.6579297991. The cubic root of 78121874 is about 427.4882848493.

The spelling of 78121874 in words is "seventy-eight million, one hundred twenty-one thousand, eight hundred seventy-four".