78619997 has 2 divisors, whose sum is σ = 78619998. Its totient is φ = 78619996.

The previous prime is 78619979. The next prime is 78620021. The reversal of 78619997 is 79991687.

Together with previous prime (78619979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72097081 + 6522916 = 8491^2 + 2554^2 .

It is a cyclic number.

It is not a de Polignac number, because 78619997 - 2¹⁶ = 78554461 is a prime.

It is a super-2 number, since 2×78619997² = 12362207856560018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78619927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39309998 + 39309999.

It is an arithmetic number, because the mean of its divisors is an integer number (39309999).

Almost surely, 2^78619997 is an apocalyptic number.

It is an amenable number.

78619997 is a deficient number, since it is larger than the sum of its proper divisors (1).

78619997 is an equidigital number, since it uses as much as digits as its factorization.

78619997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1714608, while the sum is 56.

The square root of 78619997 is about 8866.7918098938. The cubic root of 78619997 is about 428.3949483483.

The spelling of 78619997 in words is "seventy-eight million, six hundred nineteen thousand, nine hundred ninety-seven".