820783638 has 32 divisors (see below), whose sum is σ = 1827237600. Its totient is φ = 273103488.

The previous prime is 820783583. The next prime is 820783651. The reversal of 820783638 is 836387028.

820783638 is a `hidden beast` number, since 8 + 2 + 0 + 7 + 8 + 3 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 820783593 and 820783602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17370 + ... + 44082.

It is an arithmetic number, because the mean of its divisors is an integer number (57101175).

Almost surely, 2^820783638 is an apocalyptic number.

820783638 is an abundant number, since it is smaller than the sum of its proper divisors (1006453962).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820783638 is a wasteful number, since it uses less digits than its factorization.

820783638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27293 (or 27287 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 820783638 is about 28649.3217720769. The cubic root of 820783638 is about 936.2882289532.

The spelling of 820783638 in words is "eight hundred twenty million, seven hundred eighty-three thousand, six hundred thirty-eight".