77551 has 2 divisors, whose sum is σ = 77552. Its totient is φ = 77550.

The previous prime is 77549. The next prime is 77557. The reversal of 77551 is 15577.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77551 - 2¹ = 77549 is a prime.

Together with 77549, it forms a pair of twin primes.

It is an Ulam number.

It is a plaindrome in base 16.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38775 + 38776.

It is an arithmetic number, because the mean of its divisors is an integer number (38776).

2⁷⁷⁵⁵¹ is an apocalyptic number.

77551 is a deficient number, since it is larger than the sum of its proper divisors (1).

77551 is an equidigital number, since it uses as much as digits as its factorization.

77551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1225, while the sum is 25.

The square root of 77551 is about 278.4798017810. The cubic root of 77551 is about 42.6444450801.

The spelling of 77551 in words is "seventy-seven thousand, five hundred fifty-one".