1261309056 has 64 divisors (see below), whose sum is σ = 3828982080. Its totient is φ = 360373248.

The previous prime is 1261309039. The next prime is 1261309069. The reversal of 1261309056 is 6509031621.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×1261309056² = 3181801069495222272, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231931 + ... + 237306.

It is an arithmetic number, because the mean of its divisors is an integer number (59827845).

Almost surely, 2^1261309056 is an apocalyptic number.

1261309056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1261309056 is an abundant number, since it is smaller than the sum of its proper divisors (2567673024).

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

1261309056 is an equidigital number, since it uses as much as digits as its factorization.

1261309056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469261 (or 469249 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 1261309056 is about 35514.9131492673. The cubic root of 1261309056 is about 1080.4562132950.

The spelling of 1261309056 in words is "one billion, two hundred sixty-one million, three hundred nine thousand, fifty-six".