77727391 has 4 divisors (see below), whose sum is σ = 88831312. Its totient is φ = 66623472.

The previous prime is 77727371. The next prime is 77727443. The reversal of 77727391 is 19372777.

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: 19372777 = 761 ⋅25457.

It is a cyclic number.

It is not a de Polignac number, because 77727391 - 2⁹ = 77726879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77727371) 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, 5551950 + ... + 5551963.

It is an arithmetic number, because the mean of its divisors is an integer number (22207828).

Almost surely, 2^77727391 is an apocalyptic number.

77727391 is a deficient number, since it is larger than the sum of its proper divisors (11103921).

77727391 is a wasteful number, since it uses less digits than its factorization.

77727391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11103920.

The product of its digits is 129654, while the sum is 43.

The square root of 77727391 is about 8816.3139122878. The cubic root of 77727391 is about 426.7675242391.

The spelling of 77727391 in words is "seventy-seven million, seven hundred twenty-seven thousand, three hundred ninety-one".