78619691 has 2 divisors, whose sum is σ = 78619692. Its totient is φ = 78619690.

The previous prime is 78619687. The next prime is 78619693. The reversal of 78619691 is 19691687.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78619691 - 2² = 78619687 is a prime.

Together with 78619693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78619693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39309845 + 39309846.

It is an arithmetic number, because the mean of its divisors is an integer number (39309846).

Almost surely, 2^78619691 is an apocalyptic number.

78619691 is a deficient number, since it is larger than the sum of its proper divisors (1).

78619691 is an equidigital number, since it uses as much as digits as its factorization.

78619691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 47.

The square root of 78619691 is about 8866.7745544815. The cubic root of 78619691 is about 428.3943925566.

The spelling of 78619691 in words is "seventy-eight million, six hundred nineteen thousand, six hundred ninety-one".