206660491 has 4 divisors (see below), whose sum is σ = 208238184. Its totient is φ = 205082800.

The previous prime is 206660479. The next prime is 206660507. The reversal of 206660491 is 194066602.

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

It is a cyclic number.

It is not a de Polignac number, because 206660491 - 2²¹ = 204563339 is a prime.

It is a super-2 number, since 2×206660491² = 85417117080722162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206660401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 788650 + ... + 788911.

It is an arithmetic number, because the mean of its divisors is an integer number (52059546).

Almost surely, 2^206660491 is an apocalyptic number.

206660491 is a deficient number, since it is larger than the sum of its proper divisors (1577693).

206660491 is a wasteful number, since it uses less digits than its factorization.

206660491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1577692.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 206660491 is about 14375.6909746975. The cubic root of 206660491 is about 591.2245857068.

The spelling of 206660491 in words is "two hundred six million, six hundred sixty thousand, four hundred ninety-one".