91271281 has 4 divisors (see below), whose sum is σ = 92556864. Its totient is φ = 89985700.

The previous prime is 91271273. The next prime is 91271293. The reversal of 91271281 is 18217219.

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 91271281 - 2³ = 91271273 is a prime.

It is a super-2 number, since 2×91271281² = 16660893470761922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91271221) 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, 642685 + ... + 642826.

It is an arithmetic number, because the mean of its divisors is an integer number (23139216).

Almost surely, 2^91271281 is an apocalyptic number.

91271281 is the 4273-rd centered decagonal number.

It is an amenable number.

91271281 is a deficient number, since it is larger than the sum of its proper divisors (1285583).

91271281 is a wasteful number, since it uses less digits than its factorization.

91271281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1285582.

The product of its digits is 2016, while the sum is 31.

The square root of 91271281 is about 9553.6004207838. The cubic root of 91271281 is about 450.2406630384.

The spelling of 91271281 in words is "ninety-one million, two hundred seventy-one thousand, two hundred eighty-one".