730821 has 16 divisors (see below), whose sum is σ = 1199744. Its totient is φ = 385344.

The previous prime is 730819. The next prime is 730823. The reversal of 730821 is 128037.

730821 is digitally balanced in base 2 and base 7, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (730819) and next prime (730823).

It is not a de Polignac number, because 730821 - 2¹ = 730819 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

730821 is strictly pandigital in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (730823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1066 + ... + 1611.

It is an arithmetic number, because the mean of its divisors is an integer number (74984).

2⁷³⁰⁸²¹ is an apocalyptic number.

It is an amenable number.

730821 is a deficient number, since it is larger than the sum of its proper divisors (468923).

730821 is a wasteful number, since it uses less digits than its factorization.

730821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2700.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 730821 is about 854.8806934304. The cubic root of 730821 is about 90.0748759609.

Adding to 730821 its reverse (128037), we get a palindrome (858858).

It can be divided in two parts, 730 and 821, that added together give a palindrome (1551).

The spelling of 730821 in words is "seven hundred thirty thousand, eight hundred twenty-one".