820479640 has 32 divisors (see below), whose sum is σ = 1858318560. Its totient is φ = 326016000.

The previous prime is 820479637. The next prime is 820479677. The reversal of 820479640 is 46974028.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 820479593 and 820479602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61881 + ... + 73960.

It is an arithmetic number, because the mean of its divisors is an integer number (58072455).

Almost surely, 2^820479640 is an apocalyptic number.

It is an amenable number.

820479640 is an abundant number, since it is smaller than the sum of its proper divisors (1037838920).

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

820479640 is a wasteful number, since it uses less digits than its factorization.

820479640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136003 (or 135999 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 820479640 is about 28644.0157799147. The cubic root of 820479640 is about 936.1726219962.

The spelling of 820479640 in words is "eight hundred twenty million, four hundred seventy-nine thousand, six hundred forty".