920860821 has 36 divisors (see below), whose sum is σ = 1464978528. Its totient is φ = 556264368.

The previous prime is 920860799. The next prime is 920860877. The reversal of 920860821 is 128068029.

920860821 is a `hidden beast` number, since 9 + 20 + 8 + 608 + 21 = 666.

It is not a de Polignac number, because 920860821 - 2¹³ = 920852629 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (920860121) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 68566 + ... + 80888.

It is an arithmetic number, because the mean of its divisors is an integer number (40693848).

Almost surely, 2^920860821 is an apocalyptic number.

It is an amenable number.

920860821 is a deficient number, since it is larger than the sum of its proper divisors (544117707).

920860821 is a wasteful number, since it uses less digits than its factorization.

920860821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12390 (or 12368 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 920860821 is about 30345.6886723633. The cubic root of 920860821 is about 972.8920740080.

The spelling of 920860821 in words is "nine hundred twenty million, eight hundred sixty thousand, eight hundred twenty-one".