78561331 has 2 divisors, whose sum is σ = 78561332. Its totient is φ = 78561330.

The previous prime is 78561283. The next prime is 78561337. The reversal of 78561331 is 13316587.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78561331 - 2⁹ = 78560819 is a prime.

It is a super-2 number, since 2×78561331² = 12343765456983122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78561337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39280665 + 39280666.

It is an arithmetic number, because the mean of its divisors is an integer number (39280666).

Almost surely, 2^78561331 is an apocalyptic number.

78561331 is a deficient number, since it is larger than the sum of its proper divisors (1).

78561331 is an equidigital number, since it uses as much as digits as its factorization.

78561331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 34.

The square root of 78561331 is about 8863.4830061325. The cubic root of 78561331 is about 428.2883661691.

The spelling of 78561331 in words is "seventy-eight million, five hundred sixty-one thousand, three hundred thirty-one".