97991471 has 4 divisors (see below), whose sum is σ = 98157312. Its totient is φ = 97825632.

The previous prime is 97991461. The next prime is 97991479. The reversal of 97991471 is 17419979.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17419979 = 19 ⋅916841.

It is a cyclic number.

It is not a de Polignac number, because 97991471 - 2⁶ = 97991407 is a prime.

It is a super-3 number, since 3×97991471³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97991479) 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, 82031 + ... + 83216.

It is an arithmetic number, because the mean of its divisors is an integer number (24539328).

Almost surely, 2^97991471 is an apocalyptic number.

97991471 is a deficient number, since it is larger than the sum of its proper divisors (165841).

97991471 is a wasteful number, since it uses less digits than its factorization.

97991471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165840.

The product of its digits is 142884, while the sum is 47.

The square root of 97991471 is about 9899.0641476859. The cubic root of 97991471 is about 461.0302538480.

The spelling of 97991471 in words is "ninety-seven million, nine hundred ninety-one thousand, four hundred seventy-one".