829981021 has 4 divisors (see below), whose sum is σ = 878803452. Its totient is φ = 781158592.

The previous prime is 829981001. The next prime is 829981039. The reversal of 829981021 is 120189928.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 285272100 + 544708921 = 16890^2 + 23339^2 .

It is a cyclic number.

It is not a de Polignac number, because 829981021 - 2⁹ = 829980509 is a prime.

It is a super-3 number, since 3×829981021³ (a number of 28 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (829981001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24411190 + ... + 24411223.

It is an arithmetic number, because the mean of its divisors is an integer number (219700863).

Almost surely, 2^829981021 is an apocalyptic number.

It is an amenable number.

829981021 is a deficient number, since it is larger than the sum of its proper divisors (48822431).

829981021 is a wasteful number, since it uses less digits than its factorization.

829981021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48822430.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 829981021 is about 28809.3911945393. The cubic root of 829981021 is about 939.7724743573.

The spelling of 829981021 in words is "eight hundred twenty-nine million, nine hundred eighty-one thousand, twenty-one".