77257321 has 4 divisors (see below), whose sum is σ = 77657812. Its totient is φ = 76856832.

The previous prime is 77257319. The next prime is 77257343. The reversal of 77257321 is 12375277.

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: 12375277 = 683 ⋅18119.

It can be written as a sum of positive squares in 2 ways, for example, as 15713296 + 61544025 = 3964^2 + 7845^2 .

It is a cyclic number.

It is not a de Polignac number, because 77257321 - 2¹ = 77257319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77257351) 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, 199956 + ... + 200341.

It is an arithmetic number, because the mean of its divisors is an integer number (19414453).

Almost surely, 2^77257321 is an apocalyptic number.

It is an amenable number.

77257321 is a deficient number, since it is larger than the sum of its proper divisors (400491).

77257321 is a wasteful number, since it uses less digits than its factorization.

77257321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400490.

The product of its digits is 20580, while the sum is 34.

The square root of 77257321 is about 8789.6143828953. The cubic root of 77257321 is about 425.9054669856.

The spelling of 77257321 in words is "seventy-seven million, two hundred fifty-seven thousand, three hundred twenty-one".