20439397440 has 1680 divisors, whose sum is σ = 98102928000. Its totient is φ = 4023613440.

The previous prime is 20439397423. The next prime is 20439397463. The reversal of 20439397440 is 4479393402.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 1075757751 + ... + 1075757769.

It is an arithmetic number, because the mean of its divisors is an integer number (58394600).

Almost surely, 2^20439397440 is an apocalyptic number.

20439397440 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 20439397440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49051464000).

20439397440 is an abundant number, since it is smaller than the sum of its proper divisors (77663530560).

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

20439397440 is a wasteful number, since it uses less digits than its factorization.

20439397440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 45.

The spelling of 20439397440 in words is "twenty billion, four hundred thirty-nine million, three hundred ninety-seven thousand, four hundred forty".