1281209664 has 336 divisors, whose sum is σ = 4269735936. Its totient is φ = 337075200.

The previous prime is 1281209621. The next prime is 1281209669. The reversal of 1281209664 is 4669021821.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281209669) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6707809 + ... + 6707999.

Almost surely, 2^1281209664 is an apocalyptic number.

1281209664 is a gapful number since it is divisible by the number (14) 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 1281209664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2134867968).

1281209664 is an abundant number, since it is smaller than the sum of its proper divisors (2988526272).

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

1281209664 is a wasteful number, since it uses less digits than its factorization.

1281209664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 1281209664 is about 35793.9892160681. The cubic root of 1281209664 is about 1086.1089736637.

The spelling of 1281209664 in words is "one billion, two hundred eighty-one million, two hundred nine thousand, six hundred sixty-four".