821699730 has 24 divisors (see below), whose sum is σ = 2136419532. Its totient is φ = 219119904.

The previous prime is 821699729. The next prime is 821699761. The reversal of 821699730 is 37996128.

It can be written as a sum of positive squares in 2 ways, for example, as 794732481 + 26967249 = 28191^2 + 5193^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4564909 + ... + 4565088.

Almost surely, 2^821699730 is an apocalyptic number.

821699730 is an abundant number, since it is smaller than the sum of its proper divisors (1314719802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821699730 is a wasteful number, since it uses less digits than its factorization.

821699730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9130010 (or 9130007 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 821699730 is about 28665.3053358934. The cubic root of 821699730 is about 936.6364357181.

The spelling of 821699730 in words is "eight hundred twenty-one million, six hundred ninety-nine thousand, seven hundred thirty".