97281781 has 4 divisors (see below), whose sum is σ = 99544192. Its totient is φ = 95019372.

The previous prime is 97281713. The next prime is 97281799. The reversal of 97281781 is 18718279.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18718279 = 401 ⋅46679.

It is a cyclic number.

It is not a de Polignac number, because 97281781 - 2⁹ = 97281269 is a prime.

It is a super-2 number, since 2×97281781² = 18927489829063922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 2262367 = 97281781 / (9 + 7 + 2 + 8 + 1 + 7 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97681781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1131141 + ... + 1131226.

It is an arithmetic number, because the mean of its divisors is an integer number (24886048).

Almost surely, 2^97281781 is an apocalyptic number.

It is an amenable number.

97281781 is a deficient number, since it is larger than the sum of its proper divisors (2262411).

97281781 is a wasteful number, since it uses less digits than its factorization.

97281781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2262410.

The product of its digits is 56448, while the sum is 43.

The square root of 97281781 is about 9863.1526906968. The cubic root of 97281781 is about 459.9145729831.

The spelling of 97281781 in words is "ninety-seven million, two hundred eighty-one thousand, seven hundred eighty-one".