91418381 has 4 divisors (see below), whose sum is σ = 91649052. Its totient is φ = 91187712.

The previous prime is 91418377. The next prime is 91418389. The reversal of 91418381 is 18381419.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 46648900 + 44769481 = 6830^2 + 6691^2 .

It is a cyclic number.

It is not a de Polignac number, because 91418381 - 2² = 91418377 is a prime.

It is a super-2 number, since 2×91418381² = 16714640769322322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91418389) 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, 114740 + ... + 115533.

It is an arithmetic number, because the mean of its divisors is an integer number (22912263).

Almost surely, 2^91418381 is an apocalyptic number.

It is an amenable number.

91418381 is a deficient number, since it is larger than the sum of its proper divisors (230671).

91418381 is a wasteful number, since it uses less digits than its factorization.

91418381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230670.

The product of its digits is 6912, while the sum is 35.

The square root of 91418381 is about 9561.2959895612. The cubic root of 91418381 is about 450.4824143389.

The spelling of 91418381 in words is "ninety-one million, four hundred eighteen thousand, three hundred eighty-one".