247921 has 8 divisors (see below), whose sum is σ = 262080. Its totient is φ = 234192.

The previous prime is 247913. The next prime is 247939. The reversal of 247921 is 129742.

247921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 247921 - 2³ = 247913 is a prime.

It is a super-2 number, since 2×247921² = 122929644482, which contains 22 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 (247901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2356 + ... + 2458.

It is an arithmetic number, because the mean of its divisors is an integer number (32760).

2²⁴⁷⁹²¹ is an apocalyptic number.

It is an amenable number.

247921 is a deficient number, since it is larger than the sum of its proper divisors (14159).

247921 is a wasteful number, since it uses less digits than its factorization.

247921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215.

The product of its digits is 1008, while the sum is 25.

The square root of 247921 is about 497.9166596932. The cubic root of 247921 is about 62.8209411277.

It can be divided in two parts, 2479 and 21, that added together give a square (2500 = 50²).

The spelling of 247921 in words is "two hundred forty-seven thousand, nine hundred twenty-one".