266721947 has 4 divisors (see below), whose sum is σ = 268104120. Its totient is φ = 265339776.

The previous prime is 266721929. The next prime is 266721989. The reversal of 266721947 is 749127662.

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 266721947 - 2⁸ = 266721691 is a prime.

It is a super-2 number, since 2×266721947² = 142281194022941618, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 266721898 and 266721907.

It is not an unprimeable number, because it can be changed into a prime (266721047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 690797 + ... + 691182.

It is an arithmetic number, because the mean of its divisors is an integer number (67026030).

Almost surely, 2^266721947 is an apocalyptic number.

266721947 is a deficient number, since it is larger than the sum of its proper divisors (1382173).

266721947 is a wasteful number, since it uses less digits than its factorization.

266721947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1382172.

The product of its digits is 254016, while the sum is 44.

The square root of 266721947 is about 16331.6241384622. The cubic root of 266721947 is about 643.7040638099.

The spelling of 266721947 in words is "two hundred sixty-six million, seven hundred twenty-one thousand, nine hundred forty-seven".