77389381 has 4 divisors (see below), whose sum is σ = 78849612. Its totient is φ = 75929152.

The previous prime is 77389373. The next prime is 77389387. The reversal of 77389381 is 18398377.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18398377 = 173 ⋅106349.

It can be written as a sum of positive squares in 2 ways, for example, as 41796225 + 35593156 = 6465^2 + 5966^2 .

It is a cyclic number.

It is not a de Polignac number, because 77389381 - 2³ = 77389373 is a prime.

It is a super-2 number, since 2×77389381² = 11978232583126322, 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 (77389387) 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, 730036 + ... + 730141.

It is an arithmetic number, because the mean of its divisors is an integer number (19712403).

Almost surely, 2^77389381 is an apocalyptic number.

It is an amenable number.

77389381 is a deficient number, since it is larger than the sum of its proper divisors (1460231).

77389381 is a wasteful number, since it uses less digits than its factorization.

77389381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1460230.

The product of its digits is 254016, while the sum is 46.

The square root of 77389381 is about 8797.1234503103. The cubic root of 77389381 is about 426.1480030459.

The spelling of 77389381 in words is "seventy-seven million, three hundred eighty-nine thousand, three hundred eighty-one".