16821814465 has 8 divisors (see below), whose sum is σ = 20190697128. Its totient is φ = 13454438400.

The previous prime is 16821814463. The next prime is 16821814489. The reversal of 16821814465 is 56441812861.

It can be written as a sum of positive squares in 4 ways, for example, as 12650850576 + 4170963889 = 112476^2 + 64583^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16821814465 - 2¹ = 16821814463 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16821814463) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351936 + ... + 396865.

It is an arithmetic number, because the mean of its divisors is an integer number (2523837141).

Almost surely, 2^16821814465 is an apocalyptic number.

It is an amenable number.

16821814465 is a deficient number, since it is larger than the sum of its proper divisors (3368882663).

16821814465 is an equidigital number, since it uses as much as digits as its factorization.

16821814465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 753299.

The product of its digits is 368640, while the sum is 46.

The spelling of 16821814465 in words is "sixteen billion, eight hundred twenty-one million, eight hundred fourteen thousand, four hundred sixty-five".