206991471 has 4 divisors (see below), whose sum is σ = 275988632. Its totient is φ = 137994312.

The previous prime is 206991457. The next prime is 206991481. The reversal of 206991471 is 174199602.

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

It is not a de Polignac number, because 206991471 - 2²² = 202797167 is a prime.

It is a super-3 number, since 3×206991471³ (a number of 26 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 (206991401) 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, 34498576 + ... + 34498581.

It is an arithmetic number, because the mean of its divisors is an integer number (68997158).

Almost surely, 2^206991471 is an apocalyptic number.

206991471 is a deficient number, since it is larger than the sum of its proper divisors (68997161).

206991471 is an equidigital number, since it uses as much as digits as its factorization.

206991471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68997160.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 206991471 is about 14387.1981636453. The cubic root of 206991471 is about 591.5400453587.

The spelling of 206991471 in words is "two hundred six million, nine hundred ninety-one thousand, four hundred seventy-one".