20964721536 has 256 divisors, whose sum is σ = 70437772800. Its totient is φ = 6076477440.

The previous prime is 20964721493. The next prime is 20964721549. The reversal of 20964721536 is 63512746902.

20964721536 is a `hidden beast` number, since 2 + 0 + 96 + 4 + 7 + 21 + 536 = 666.

It is a super-5 number, since 5×20964721536⁵ (a number of 53 digits) contains 55555 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20964721491 and 20964721500.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 862380 + ... + 886356.

It is an arithmetic number, because the mean of its divisors is an integer number (275147550).

Almost surely, 2^20964721536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20964721536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35218886400).

20964721536 is an abundant number, since it is smaller than the sum of its proper divisors (49473051264).

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

20964721536 is a wasteful number, since it uses less digits than its factorization.

20964721536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24034 (or 24016 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 20964721536 in words is "twenty billion, nine hundred sixty-four million, seven hundred twenty-one thousand, five hundred thirty-six".