1291201856 has 56 divisors (see below), whose sum is σ = 2931785856. Its totient is φ = 552706560.

The previous prime is 1291201837. The next prime is 1291201871. The reversal of 1291201856 is 6581021921.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 617645 + ... + 619731.

Almost surely, 2^1291201856 is an apocalyptic number.

1291201856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1291201856 is an abundant number, since it is smaller than the sum of its proper divisors (1640584000).

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

1291201856 is a wasteful number, since it uses less digits than its factorization.

1291201856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3487 (or 3477 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 1291201856 is about 35933.2973159993. The cubic root of 1291201856 is about 1088.9251970185.

The spelling of 1291201856 in words is "one billion, two hundred ninety-one million, two hundred one thousand, eight hundred fifty-six".