1261220556552 has 64 divisors (see below), whose sum is σ = 3441530237760. Its totient is φ = 381983846400.

The previous prime is 1261220556461. The next prime is 1261220556571. The reversal of 1261220556552 is 2556550221621.

It is a happy number.

It is a super-3 number, since 3×1261220556552³ (a number of 37 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 780849 + ... + 1769792.

It is an arithmetic number, because the mean of its divisors is an integer number (53773909965).

Almost surely, 2^{1261220556552} is an apocalyptic number.

1261220556552 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1261220556552 is an abundant number, since it is smaller than the sum of its proper divisors (2180309681208).

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

1261220556552 is a wasteful number, since it uses less digits than its factorization.

1261220556552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2552534 (or 2552530 counting only the distinct ones).

The product of its (nonzero) digits is 360000, while the sum is 42.

The spelling of 1261220556552 in words is "one trillion, two hundred sixty-one billion, two hundred twenty million, five hundred fifty-six thousand, five hundred fifty-two".