20397607009640 has 128 divisors (see below), whose sum is σ = 54739392744960. Its totient is φ = 6688432886784.

The previous prime is 20397607009589. The next prime is 20397607009649. The reversal of 20397607009640 is 4690070679302.

It is a Cunningham number, because it is equal to 4516371²-1.

It is not an unprimeable number, because it can be changed into a prime (20397607009649) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44937902 + ... + 45389538.

It is an arithmetic number, because the mean of its divisors is an integer number (427651505820).

Almost surely, 2^{20397607009640} is an apocalyptic number.

20397607009640 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 20397607009640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27369696372480).

20397607009640 is an abundant number, since it is smaller than the sum of its proper divisors (34341785735320).

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

20397607009640 is a wasteful number, since it uses less digits than its factorization.

20397607009640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458691 (or 458687 counting only the distinct ones).

The product of its (nonzero) digits is 3429216, while the sum is 53.

The spelling of 20397607009640 in words is "twenty trillion, three hundred ninety-seven billion, six hundred seven million, nine thousand, six hundred forty".