97278781 has 2 divisors, whose sum is σ = 97278782. Its totient is φ = 97278780.

The previous prime is 97278763. The next prime is 97278791. The reversal of 97278781 is 18787279.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 86322681 + 10956100 = 9291^2 + 3310^2 .

It is a cyclic number.

It is not a de Polignac number, because 97278781 - 2⁷ = 97278653 is a prime.

It is a super-2 number, since 2×97278781² = 18926322465691922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (97278721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48639390 + 48639391.

It is an arithmetic number, because the mean of its divisors is an integer number (48639391).

Almost surely, 2^97278781 is an apocalyptic number.

It is an amenable number.

97278781 is a deficient number, since it is larger than the sum of its proper divisors (1).

97278781 is an equidigital number, since it uses as much as digits as its factorization.

97278781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 395136, while the sum is 49.

The square root of 97278781 is about 9863.0006083342. Note that the first 3 decimals coincide. The cubic root of 97278781 is about 459.9098452808.

The spelling of 97278781 in words is "ninety-seven million, two hundred seventy-eight thousand, seven hundred eighty-one".