78121047 has 4 divisors (see below), whose sum is σ = 104161400. Its totient is φ = 52080696.

The previous prime is 78121039. The next prime is 78121049. The reversal of 78121047 is 74012187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74012187 = 3 ⋅24670729.

It is not a de Polignac number, because 78121047 - 2³ = 78121039 is a prime.

It is a super-2 number, since 2×78121047² = 12205795968752418, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78121049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13020172 + ... + 13020177.

It is an arithmetic number, because the mean of its divisors is an integer number (26040350).

Almost surely, 2^78121047 is an apocalyptic number.

78121047 is a deficient number, since it is larger than the sum of its proper divisors (26040353).

78121047 is a wasteful number, since it uses less digits than its factorization.

78121047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26040352.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 78121047 is about 8838.6111465546. The cubic root of 78121047 is about 427.4867763770.

The spelling of 78121047 in words is "seventy-eight million, one hundred twenty-one thousand, forty-seven".