1020646656 has 144 divisors (see below), whose sum is σ = 3057169920. Its totient is φ = 340028928.

The previous prime is 1020646651. The next prime is 1020646657. The reversal of 1020646656 is 6566460201.

It is a happy number.

1020646656 is a `hidden beast` number, since 1 + 0 + 2 + 0 + 646 + 6 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1020646656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020646651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 558961 + ... + 560783.

Almost surely, 2^1020646656 is an apocalyptic number.

1020646656 is a gapful number since it is divisible by the number (16) 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 1020646656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1528584960).

1020646656 is an abundant number, since it is smaller than the sum of its proper divisors (2036523264).

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

1020646656 is an frugal number, since it uses more digits than its factorization.

1020646656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1860 (or 1828 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 1020646656 is about 31947.5610336689. The cubic root of 1020646656 is about 1006.8353896593.

The spelling of 1020646656 in words is "one billion, twenty million, six hundred forty-six thousand, six hundred fifty-six".