91478557 has 4 divisors (see below), whose sum is σ = 94633020. Its totient is φ = 88324096.

The previous prime is 91478549. The next prime is 91478573. The reversal of 91478557 is 75587419.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75587419 = 4583 ⋅16493.

It can be written as a sum of positive squares in 2 ways, for example, as 57244356 + 34234201 = 7566^2 + 5851^2 .

It is a cyclic number.

It is not a de Polignac number, because 91478557 - 2³ = 91478549 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 (91478657) 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, 1577188 + ... + 1577245.

It is an arithmetic number, because the mean of its divisors is an integer number (23658255).

Almost surely, 2^91478557 is an apocalyptic number.

It is an amenable number.

91478557 is a deficient number, since it is larger than the sum of its proper divisors (3154463).

91478557 is a wasteful number, since it uses less digits than its factorization.

91478557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3154462.

The product of its digits is 352800, while the sum is 46.

The square root of 91478557 is about 9564.4423256142. The cubic root of 91478557 is about 450.5812357636.

The spelling of 91478557 in words is "ninety-one million, four hundred seventy-eight thousand, five hundred fifty-seven".