20820329640 has 384 divisors, whose sum is σ = 77048496000. Its totient is φ = 4996823040.

The previous prime is 20820329557. The next prime is 20820329653. The reversal of 20820329640 is 4692302802.

20820329640 is a `hidden beast` number, since 2 + 0 + 8 + 2 + 0 + 3 + 2 + 9 + 640 = 666.

It is a super-2 number, since 2×20820329640² (a number of 21 digits) contains 22 as substring.

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 = 20820329595 and 20820329604.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 13982016 + ... + 13983504.

It is an arithmetic number, because the mean of its divisors is an integer number (200647125).

Almost surely, 2^20820329640 is an apocalyptic number.

20820329640 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 20820329640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38524248000).

20820329640 is an abundant number, since it is smaller than the sum of its proper divisors (56228166360).

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

20820329640 is a wasteful number, since it uses less digits than its factorization.

20820329640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1638 (or 1617 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

It can be divided in two parts, 20820329 and 640, that added together give a square (20820969 = 4563²).

The spelling of 20820329640 in words is "twenty billion, eight hundred twenty million, three hundred twenty-nine thousand, six hundred forty".