20851733394 has 128 divisors (see below), whose sum is σ = 48861895680. Its totient is φ = 6583514112.

The previous prime is 20851733377. The next prime is 20851733411. The reversal of 20851733394 is 49333715802.

20851733394 is a `hidden beast` number, since 208 + 51 + 7 + 3 + 3 + 394 = 666.

It is an interprime number because it is at equal distance from previous prime (20851733377) and next prime (20851733411).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21879622 + ... + 21880574.

It is an arithmetic number, because the mean of its divisors is an integer number (381733560).

Almost surely, 2^20851733394 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20851733394, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24430947840).

20851733394 is an abundant number, since it is smaller than the sum of its proper divisors (28010162286).

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

20851733394 is a wasteful number, since it uses less digits than its factorization.

20851733394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1281 (or 1275 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 20851733394 in words is "twenty billion, eight hundred fifty-one million, seven hundred thirty-three thousand, three hundred ninety-four".