78409487 has 4 divisors (see below), whose sum is σ = 84441000. Its totient is φ = 72377976.

The previous prime is 78409469. The next prime is 78409577. The reversal of 78409487 is 78490487.

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

It is a cyclic number.

It is not a de Polignac number, because 78409487 - 2²⁶ = 11300623 is a prime.

It is a super-2 number, since 2×78409487² = 12296095303206338, 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 (78409427) 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, 3015737 + ... + 3015762.

It is an arithmetic number, because the mean of its divisors is an integer number (21110250).

Almost surely, 2^78409487 is an apocalyptic number.

78409487 is a deficient number, since it is larger than the sum of its proper divisors (6031513).

78409487 is a wasteful number, since it uses less digits than its factorization.

78409487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6031512.

The product of its (nonzero) digits is 451584, while the sum is 47.

The square root of 78409487 is about 8854.9131559830. The cubic root of 78409487 is about 428.0122550862.

The spelling of 78409487 in words is "seventy-eight million, four hundred nine thousand, four hundred eighty-seven".