290721 has 4 divisors (see below), whose sum is σ = 387632. Its totient is φ = 193812.

The previous prime is 290711. The next prime is 290737. The reversal of 290721 is 127092.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 290721 - 2⁶ = 290657 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (290701) 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, 48451 + ... + 48456.

It is an arithmetic number, because the mean of its divisors is an integer number (96908).

2²⁹⁰⁷²¹ is an apocalyptic number.

It is an amenable number.

290721 is a deficient number, since it is larger than the sum of its proper divisors (96911).

290721 is an equidigital number, since it uses as much as digits as its factorization.

290721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96910.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 290721 is about 539.1854968376. The cubic root of 290721 is about 66.2458689723.

The spelling of 290721 in words is "two hundred ninety thousand, seven hundred twenty-one".