1790821813 has 4 divisors (see below), whose sum is σ = 1953623808. Its totient is φ = 1628019820.

The previous prime is 1790821811. The next prime is 1790821819. The reversal of 1790821813 is 3181280971.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1790821813 - 2¹ = 1790821811 is a prime.

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 (1790821811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81400981 + ... + 81401002.

It is an arithmetic number, because the mean of its divisors is an integer number (488405952).

Almost surely, 2^1790821813 is an apocalyptic number.

It is an amenable number.

1790821813 is a deficient number, since it is larger than the sum of its proper divisors (162801995).

1790821813 is a wasteful number, since it uses less digits than its factorization.

1790821813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162801994.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 1790821813 is about 42318.1026630448. The cubic root of 1790821813 is about 1214.3693347318.

The spelling of 1790821813 in words is "one billion, seven hundred ninety million, eight hundred twenty-one thousand, eight hundred thirteen".