77628391 has 2 divisors, whose sum is σ = 77628392. Its totient is φ = 77628390.

The previous prime is 77628379. The next prime is 77628403. The reversal of 77628391 is 19382677.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (77628379) and next prime (77628403).

It is a cyclic number.

It is not a de Polignac number, because 77628391 - 2⁵ = 77628359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77628191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38814195 + 38814196.

It is an arithmetic number, because the mean of its divisors is an integer number (38814196).

Almost surely, 2^77628391 is an apocalyptic number.

77628391 is a deficient number, since it is larger than the sum of its proper divisors (1).

77628391 is an equidigital number, since it uses as much as digits as its factorization.

77628391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 43.

The square root of 77628391 is about 8810.6975319778. The cubic root of 77628391 is about 426.5862585156.

The spelling of 77628391 in words is "seventy-seven million, six hundred twenty-eight thousand, three hundred ninety-one".