920786821 has 4 divisors (see below), whose sum is σ = 942200512. Its totient is φ = 899373132.

The previous prime is 920786813. The next prime is 920786833. The reversal of 920786821 is 128687029.

920786821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 128687029 = 101 ⋅1274129.

It is a cyclic number.

It is not a de Polignac number, because 920786821 - 2³ = 920786813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 21413647 = 920786821 / (9 + 2 + 0 + 7 + 8 + 6 + 8 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (920786891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10706781 + ... + 10706866.

It is an arithmetic number, because the mean of its divisors is an integer number (235550128).

Almost surely, 2^920786821 is an apocalyptic number.

It is an amenable number.

920786821 is a deficient number, since it is larger than the sum of its proper divisors (21413691).

920786821 is a wasteful number, since it uses less digits than its factorization.

920786821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21413690.

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 920786821 is about 30344.4693642845. The cubic root of 920786821 is about 972.8660129065.

The spelling of 920786821 in words is "nine hundred twenty million, seven hundred eighty-six thousand, eight hundred twenty-one".