20051439840 has 480 divisors, whose sum is σ = 75610402560. Its totient is φ = 4993228800.

The previous prime is 20051439839. The next prime is 20051439893. The reversal of 20051439840 is 4893415002.

It is a tau number, because it is divible by the number of its divisors (480).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20051439795 and 20051439804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11650180 + ... + 11651900.

It is an arithmetic number, because the mean of its divisors is an integer number (157521672).

Almost surely, 2^20051439840 is an apocalyptic number.

20051439840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20051439840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37805201280).

20051439840 is an abundant number, since it is smaller than the sum of its proper divisors (55558962720).

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

20051439840 is a wasteful number, since it uses less digits than its factorization.

20051439840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1808 (or 1791 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 20051439840 in words is "twenty billion, fifty-one million, four hundred thirty-nine thousand, eight hundred forty".