20840639394 has 8 divisors (see below), whose sum is σ = 41681278800. Its totient is φ = 6946879796.

The previous prime is 20840639389. The next prime is 20840639401. The reversal of 20840639394 is 49393604802.

It is a sphenic number, since it is the product of 3 distinct primes.

20840639394 is an admirable number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1736719944 + ... + 1736719955.

It is an arithmetic number, because the mean of its divisors is an integer number (5210159850).

Almost surely, 2^20840639394 is an apocalyptic number.

20840639394 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20840639394 is a wasteful number, since it uses less digits than its factorization.

20840639394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3473439904.

The product of its (nonzero) digits is 1119744, while the sum is 48.

The spelling of 20840639394 in words is "twenty billion, eight hundred forty million, six hundred thirty-nine thousand, three hundred ninety-four".