821142731 has 2 divisors, whose sum is σ = 821142732. Its totient is φ = 821142730.

The previous prime is 821142719. The next prime is 821142767. The reversal of 821142731 is 137241128.

821142731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821142731 is a prime.

It is a super-2 number, since 2×821142731² = 1348550769348276722, which contains 22 as substring.

It is equal to p_42177323 and since 821142731 and 42177323 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 821142694 and 821142703.

It is not a weakly prime, because it can be changed into another prime (821142701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410571365 + 410571366.

It is an arithmetic number, because the mean of its divisors is an integer number (410571366).

Almost surely, 2^821142731 is an apocalyptic number.

821142731 is a deficient number, since it is larger than the sum of its proper divisors (1).

821142731 is an equidigital number, since it uses as much as digits as its factorization.

821142731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 29.

The square root of 821142731 is about 28655.5881286705. The cubic root of 821142731 is about 936.4247511392.

Adding to 821142731 its reverse (137241128), we get a palindrome (958383859).

The spelling of 821142731 in words is "eight hundred twenty-one million, one hundred forty-two thousand, seven hundred thirty-one".