20649406464 has 260 divisors, whose sum is σ = 62360704120. Its totient is φ = 6808043520.

The previous prime is 20649406433. The next prime is 20649406487. The reversal of 20649406464 is 46460494602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 36163299 + ... + 36163869.

It is an arithmetic number, because the mean of its divisors is an integer number (239848862).

Almost surely, 2^20649406464 is an apocalyptic number.

20649406464 is a gapful number since it is divisible by the number (24) 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 20649406464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31180352060).

20649406464 is an abundant number, since it is smaller than the sum of its proper divisors (41711297656).

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

20649406464 is an equidigital number, since it uses as much as digits as its factorization.

20649406464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716 (or 685 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 45.

The spelling of 20649406464 in words is "twenty billion, six hundred forty-nine million, four hundred six thousand, four hundred sixty-four".