821940899629 has 2 divisors, whose sum is σ = 821940899630. Its totient is φ = 821940899628.

The previous prime is 821940899621. The next prime is 821940899687. The reversal of 821940899629 is 926998049128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 453431197129 + 368509702500 = 673373^2 + 607050^2 .

It is a cyclic number.

It is not a de Polignac number, because 821940899629 - 2³ = 821940899621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821940899621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410970449814 + 410970449815.

It is an arithmetic number, because the mean of its divisors is an integer number (410970449815).

Almost surely, 2^821940899629 is an apocalyptic number.

It is an amenable number.

821940899629 is a deficient number, since it is larger than the sum of its proper divisors (1).

821940899629 is an equidigital number, since it uses as much as digits as its factorization.

821940899629 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40310784, while the sum is 67.

The spelling of 821940899629 in words is "eight hundred twenty-one billion, nine hundred forty million, eight hundred ninety-nine thousand, six hundred twenty-nine".