163378781 has 2 divisors, whose sum is σ = 163378782. Its totient is φ = 163378780.

The previous prime is 163378751. The next prime is 163378799. The reversal of 163378781 is 187873361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150454756 + 12924025 = 12266^2 + 3595^2 .

It is a cyclic number.

It is not a de Polignac number, because 163378781 - 2²² = 159184477 is a prime.

It is a super-2 number, since 2×163378781² = 53385252162091922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163378741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81689390 + 81689391.

It is an arithmetic number, because the mean of its divisors is an integer number (81689391).

Almost surely, 2^163378781 is an apocalyptic number.

It is an amenable number.

163378781 is a deficient number, since it is larger than the sum of its proper divisors (1).

163378781 is an equidigital number, since it uses as much as digits as its factorization.

163378781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 169344, while the sum is 44.

The square root of 163378781 is about 12781.9709356578. The cubic root of 163378781 is about 546.6783611336.

The spelling of 163378781 in words is "one hundred sixty-three million, three hundred seventy-eight thousand, seven hundred eighty-one".