78889381 has 2 divisors, whose sum is σ = 78889382. Its totient is φ = 78889380.

The previous prime is 78889339. The next prime is 78889411. The reversal of 78889381 is 18398887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66569281 + 12320100 = 8159^2 + 3510^2 .

It is a cyclic number.

It is not a de Polignac number, because 78889381 - 2⁷ = 78889253 is a prime.

It is a super-2 number, since 2×78889381² = 12447068869126322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78889301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39444690 + 39444691.

It is an arithmetic number, because the mean of its divisors is an integer number (39444691).

Almost surely, 2^78889381 is an apocalyptic number.

It is an amenable number.

78889381 is a deficient number, since it is larger than the sum of its proper divisors (1).

78889381 is an equidigital number, since it uses as much as digits as its factorization.

78889381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 774144, while the sum is 52.

The square root of 78889381 is about 8881.9694325076. The cubic root of 78889381 is about 428.8836755337.

The spelling of 78889381 in words is "seventy-eight million, eight hundred eighty-nine thousand, three hundred eighty-one".