20647965636 has 81 divisors (see below), whose sum is σ = 54259327759. Its totient is φ = 6874895736.

The previous prime is 20647965631. The next prime is 20647965641. The reversal of 20647965636 is 63656974602.

The square root of 20647965636 is 143694.

It is a perfect power (a square), and thus also a powerful number.

20647965636 is a `hidden beast` number, since 2 + 0 + 6 + 4 + 79 + 6 + 563 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (20647965631) and next prime (20647965641).

It is a tau number, because it is divible by the number of its divisors (81).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20647965631) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 23277985 + ... + 23278871.

Almost surely, 2^20647965636 is an apocalyptic number.

20647965636 is the 143694-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20647965636

20647965636 is an abundant number, since it is smaller than the sum of its proper divisors (33611362123).

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

20647965636 is an frugal number, since it uses more digits than its factorization.

20647965636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1802 (or 892 counting only the distinct ones).

The product of its (nonzero) digits is 9797760, while the sum is 54.

The spelling of 20647965636 in words is "twenty billion, six hundred forty-seven million, nine hundred sixty-five thousand, six hundred thirty-six".