826135721 has 2 divisors, whose sum is σ = 826135722. Its totient is φ = 826135720.

The previous prime is 826135703. The next prime is 826135733. The reversal of 826135721 is 127531628.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 824838400 + 1297321 = 28720^2 + 1139^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-826135721 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (826132721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 413067860 + 413067861.

It is an arithmetic number, because the mean of its divisors is an integer number (413067861).

Almost surely, 2^826135721 is an apocalyptic number.

It is an amenable number.

826135721 is a deficient number, since it is larger than the sum of its proper divisors (1).

826135721 is an equidigital number, since it uses as much as digits as its factorization.

826135721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 35.

The square root of 826135721 is about 28742.5767981926. The cubic root of 826135721 is about 938.3189060715.

The spelling of 826135721 in words is "eight hundred twenty-six million, one hundred thirty-five thousand, seven hundred twenty-one".