1296721536 has 128 divisors (see below), whose sum is σ = 3859565760. Its totient is φ = 382279680.

The previous prime is 1296721483. The next prime is 1296721553. The reversal of 1296721536 is 6351276921.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152140 + ... + 160436.

Almost surely, 2^1296721536 is an apocalyptic number.

1296721536 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 1296721536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1929782880).

1296721536 is an abundant number, since it is smaller than the sum of its proper divisors (2562844224).

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

1296721536 is a wasteful number, since it uses less digits than its factorization.

1296721536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8362 (or 8350 counting only the distinct ones).

The product of its digits is 136080, while the sum is 42.

The square root of 1296721536 is about 36010.0199389003. The cubic root of 1296721536 is about 1090.4746511749.

The spelling of 1296721536 in words is "one billion, two hundred ninety-six million, seven hundred twenty-one thousand, five hundred thirty-six".