91863281 has 4 divisors (see below), whose sum is σ = 92298864. Its totient is φ = 91427700.

The previous prime is 91863269. The next prime is 91863283. The reversal of 91863281 is 18236819.

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.

It is a cyclic number.

It is not a de Polignac number, because 91863281 - 2¹⁴ = 91846897 is a prime.

It is a super-2 number, since 2×91863281² = 16877724792169922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91863283) 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, 217475 + ... + 217896.

It is an arithmetic number, because the mean of its divisors is an integer number (23074716).

Almost surely, 2^91863281 is an apocalyptic number.

It is an amenable number.

91863281 is a deficient number, since it is larger than the sum of its proper divisors (435583).

91863281 is a wasteful number, since it uses less digits than its factorization.

91863281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435582.

The product of its digits is 20736, while the sum is 38.

The square root of 91863281 is about 9584.5334263072. The cubic root of 91863281 is about 451.2120100614.

The spelling of 91863281 in words is "ninety-one million, eight hundred sixty-three thousand, two hundred eighty-one".