20783838640 has 40 divisors (see below), whose sum is σ = 48329920080. Its totient is φ = 8312246016.

The previous prime is 20783838553. The next prime is 20783838683. The reversal of 20783838640 is 4683838702.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×20783838640² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 628602 + ... + 660838.

It is an arithmetic number, because the mean of its divisors is an integer number (1208248002).

Almost surely, 2^20783838640 is an apocalyptic number.

20783838640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20783838640 is an abundant number, since it is smaller than the sum of its proper divisors (27546081440).

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

20783838640 is a wasteful number, since it uses less digits than its factorization.

20783838640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40309 (or 40303 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 49.

The spelling of 20783838640 in words is "twenty billion, seven hundred eighty-three million, eight hundred thirty-eight thousand, six hundred forty".