821732401 has 6 divisors (see below), whose sum is σ = 955892850. Its totient is φ = 704342016.

The previous prime is 821732393. The next prime is 821732419. The reversal of 821732401 is 104237128.

It can be written as a sum of positive squares in only one way, i.e., 821682225 + 50176 = 28665^2 + 224^2 .

It is not a de Polignac number, because 821732401 - 2³ = 821732393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 821732401.

It is not an unprimeable number, because it can be changed into a prime (821732441) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8384976 + ... + 8385073.

It is an arithmetic number, because the mean of its divisors is an integer number (159315475).

Almost surely, 2^821732401 is an apocalyptic number.

It is an amenable number.

821732401 is a deficient number, since it is larger than the sum of its proper divisors (134160449).

821732401 is a wasteful number, since it uses less digits than its factorization.

821732401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16770063 (or 16770056 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 821732401 is about 28665.8752003144. The cubic root of 821732401 is about 936.6488491916.

Adding to 821732401 its reverse (104237128), we get a palindrome (925969529).

The spelling of 821732401 in words is "eight hundred twenty-one million, seven hundred thirty-two thousand, four hundred one".