821265457 has 2 divisors, whose sum is σ = 821265458. Its totient is φ = 821265456.

The previous prime is 821265437. The next prime is 821265463. The reversal of 821265457 is 754562128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 543076416 + 278189041 = 23304^2 + 16679^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821265457 is a prime.

It is a super-2 number, since 2×821265457² = 1348953901722837698, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (821265407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410632728 + 410632729.

It is an arithmetic number, because the mean of its divisors is an integer number (410632729).

Almost surely, 2^821265457 is an apocalyptic number.

It is an amenable number.

821265457 is a deficient number, since it is larger than the sum of its proper divisors (1).

821265457 is an equidigital number, since it uses as much as digits as its factorization.

821265457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 134400, while the sum is 40.

The square root of 821265457 is about 28657.7294459976. The cubic root of 821265457 is about 936.4714007389.

The spelling of 821265457 in words is "eight hundred twenty-one million, two hundred sixty-five thousand, four hundred fifty-seven".