1643261560 has 32 divisors (see below), whose sum is σ = 3698492400. Its totient is φ = 657099520.

The previous prime is 1643261527. The next prime is 1643261561. The reversal of 1643261560 is 651623461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643261561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 249915 + ... + 256405.

Almost surely, 2^1643261560 is an apocalyptic number.

1643261560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643261560 is an abundant number, since it is smaller than the sum of its proper divisors (2055230840).

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

1643261560 is a wasteful number, since it uses less digits than its factorization.

1643261560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12831 (or 12827 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 1643261560 is about 40537.1627028829. The cubic root of 1643261560 is about 1180.0549529134.

The spelling of 1643261560 in words is "one billion, six hundred forty-three million, two hundred sixty-one thousand, five hundred sixty".