78389477 has 4 divisors (see below), whose sum is σ = 78417036. Its totient is φ = 78361920.

The previous prime is 78389449. The next prime is 78389501. The reversal of 78389477 is 77498387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77498387 = 37 ⋅2094551.

It can be written as a sum of positive squares in 2 ways, for example, as 73376356 + 5013121 = 8566^2 + 2239^2 .

It is a cyclic number.

It is not a de Polignac number, because 78389477 - 2¹² = 78385381 is a prime.

It is a super-2 number, since 2×78389477² = 12289820208667058, 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 (78389777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8948 + ... + 15389.

It is an arithmetic number, because the mean of its divisors is an integer number (19604259).

Almost surely, 2^78389477 is an apocalyptic number.

It is an amenable number.

78389477 is a deficient number, since it is larger than the sum of its proper divisors (27559).

78389477 is a wasteful number, since it uses less digits than its factorization.

78389477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27558.

The product of its digits is 2370816, while the sum is 53.

The square root of 78389477 is about 8853.7832026767. The cubic root of 78389477 is about 427.9758425967.

The spelling of 78389477 in words is "seventy-eight million, three hundred eighty-nine thousand, four hundred seventy-seven".