91661477 has 4 divisors (see below), whose sum is σ = 92168076. Its totient is φ = 91154880.

The previous prime is 91661461. The next prime is 91661483. The reversal of 91661477 is 77416619.

It is a Cunningham number, because it is equal to 9574²+1.

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 1012036 + 90649441 = 1006^2 + 9521^2 .

It is a cyclic number.

It is not a de Polignac number, because 91661477 - 2⁴ = 91661461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91661407) 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, 253028 + ... + 253389.

It is an arithmetic number, because the mean of its divisors is an integer number (23042019).

Almost surely, 2^91661477 is an apocalyptic number.

It is an amenable number.

91661477 is a deficient number, since it is larger than the sum of its proper divisors (506599).

91661477 is a wasteful number, since it uses less digits than its factorization.

91661477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506598.

The product of its digits is 63504, while the sum is 41.

The square root of 91661477 is about 9574.0000522248. Note that the first 4 decimals coincide. The cubic root of 91661477 is about 450.8813623636.

The spelling of 91661477 in words is "ninety-one million, six hundred sixty-one thousand, four hundred seventy-seven".