78621811 has 2 divisors, whose sum is σ = 78621812. Its totient is φ = 78621810.

The previous prime is 78621793. The next prime is 78621817. The reversal of 78621811 is 11812687.

It is a strong prime.

It is an emirp because it is prime and its reverse (11812687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78621811 - 2⁹ = 78621299 is a prime.

It is not a weakly prime, because it can be changed into another prime (78621817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39310905 + 39310906.

It is an arithmetic number, because the mean of its divisors is an integer number (39310906).

Almost surely, 2^78621811 is an apocalyptic number.

78621811 is a deficient number, since it is larger than the sum of its proper divisors (1).

78621811 is an equidigital number, since it uses as much as digits as its factorization.

78621811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 34.

The square root of 78621811 is about 8866.8941010931. The cubic root of 78621811 is about 428.3982431099.

The spelling of 78621811 in words is "seventy-eight million, six hundred twenty-one thousand, eight hundred eleven".