78774881 has 2 divisors, whose sum is σ = 78774882. Its totient is φ = 78774880.

The previous prime is 78774847. The next prime is 78774911. The reversal of 78774881 is 18847787.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41075281 + 37699600 = 6409^2 + 6140^2 .

It is a cyclic number.

It is not a de Polignac number, because 78774881 - 2¹⁸ = 78512737 is a prime.

It is a super-2 number, since 2×78774881² = 12410963753128322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78774841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39387440 + 39387441.

It is an arithmetic number, because the mean of its divisors is an integer number (39387441).

Almost surely, 2^78774881 is an apocalyptic number.

It is an amenable number.

78774881 is a deficient number, since it is larger than the sum of its proper divisors (1).

78774881 is an equidigital number, since it uses as much as digits as its factorization.

78774881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 702464, while the sum is 50.

The square root of 78774881 is about 8875.5214494699. The cubic root of 78774881 is about 428.6760812312.

The spelling of 78774881 in words is "seventy-eight million, seven hundred seventy-four thousand, eight hundred eighty-one".