829921021 has 2 divisors, whose sum is σ = 829921022. Its totient is φ = 829921020.

The previous prime is 829920979. The next prime is 829921031. The reversal of 829921021 is 120129928.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 821452921 + 8468100 = 28661^2 + 2910^2 .

It is a cyclic number.

It is not a de Polignac number, because 829921021 - 2¹³ = 829912829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (829921031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 414960510 + 414960511.

It is an arithmetic number, because the mean of its divisors is an integer number (414960511).

Almost surely, 2^829921021 is an apocalyptic number.

It is an amenable number.

829921021 is a deficient number, since it is larger than the sum of its proper divisors (1).

829921021 is an equidigital number, since it uses as much as digits as its factorization.

829921021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 829921021 is about 28808.3498486116. The cubic root of 829921021 is about 939.7498281739.

The spelling of 829921021 in words is "eight hundred twenty-nine million, nine hundred twenty-one thousand, twenty-one".