821724941 has 4 divisors (see below), whose sum is σ = 825619584. Its totient is φ = 817830300.

The previous prime is 821724931. The next prime is 821724989. The reversal of 821724941 is 149427128.

It is a happy number.

821724941 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is not a de Polignac number, because 821724941 - 2⁶ = 821724877 is a prime.

It is a super-2 number, since 2×821724941² = 1350463757322906962, 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 = 821724895 and 821724904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821724931) 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, 1947005 + ... + 1947426.

It is an arithmetic number, because the mean of its divisors is an integer number (206404896).

Almost surely, 2^821724941 is an apocalyptic number.

It is an amenable number.

821724941 is a deficient number, since it is larger than the sum of its proper divisors (3894643).

821724941 is a wasteful number, since it uses less digits than its factorization.

821724941 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3894642.

The product of its digits is 32256, while the sum is 38.

The square root of 821724941 is about 28665.7450801475. The cubic root of 821724941 is about 936.6460147646.

The spelling of 821724941 in words is "eight hundred twenty-one million, seven hundred twenty-four thousand, nine hundred forty-one".