20634915840 has 704 divisors, whose sum is σ = 83761274880. Its totient is φ = 4211343360.

The previous prime is 20634915839. The next prime is 20634915881. The reversal of 20634915840 is 4851943602.

It is a tau number, because it is divible by the number of its divisors (704).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 20634915792 and 20634915801.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 86338441 + ... + 86338679.

Almost surely, 2^20634915840 is an apocalyptic number.

20634915840 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 20634915840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41880637440).

20634915840 is an abundant number, since it is smaller than the sum of its proper divisors (63126359040).

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

20634915840 is a wasteful number, since it uses less digits than its factorization.

20634915840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 340 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 20634915840 in words is "twenty billion, six hundred thirty-four million, nine hundred fifteen thousand, eight hundred forty".