821038997 has 2 divisors, whose sum is σ = 821038998. Its totient is φ = 821038996.

The previous prime is 821038993. The next prime is 821039017. The reversal of 821038997 is 799830128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 730674961 + 90364036 = 27031^2 + 9506^2 .

It is a cyclic number.

It is not a de Polignac number, because 821038997 - 2² = 821038993 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821038993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410519498 + 410519499.

It is an arithmetic number, because the mean of its divisors is an integer number (410519499).

Almost surely, 2^821038997 is an apocalyptic number.

It is an amenable number.

821038997 is a deficient number, since it is larger than the sum of its proper divisors (1).

821038997 is an equidigital number, since it uses as much as digits as its factorization.

821038997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 47.

The square root of 821038997 is about 28653.7780580502. The cubic root of 821038997 is about 936.3853169977.

The spelling of 821038997 in words is "eight hundred twenty-one million, thirty-eight thousand, nine hundred ninety-seven".