826442809921 has 3 divisors (see below), whose sum is σ = 826443719011. Its totient is φ = 826441900832.

The previous prime is 826442809901. The next prime is 826442809939. The reversal of 826442809921 is 129908244628.

The square root of 826442809921 is 909089.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 409230163521 + 417212646400 = 639711^2 + 645920^2 .

It is not a de Polignac number, because 826442809921 - 2¹³ = 826442801729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (826442809901) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 454545 + ... + 1363633.

Almost surely, 2^826442809921 is an apocalyptic number.

826442809921 is the 909089-th square number.

826442809921 is the 454545-th centered octagonal number.

It is an amenable number.

826442809921 is a deficient number, since it is larger than the sum of its proper divisors (909090).

826442809921 is an frugal number, since it uses more digits than its factorization.

826442809921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818178 (or 909089 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 55.

The spelling of 826442809921 in words is "eight hundred twenty-six billion, four hundred forty-two million, eight hundred nine thousand, nine hundred twenty-one".