1266621556 has 12 divisors (see below), whose sum is σ = 2220367968. Its totient is φ = 632230712.

The previous prime is 1266621553. The next prime is 1266621571. The reversal of 1266621556 is 6551266621.

It is a super-2 number, since 2×1266621556² = 3208660332247722272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266621553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267376 + ... + 272071.

It is an arithmetic number, because the mean of its divisors is an integer number (185030664).

Almost surely, 2^1266621556 is an apocalyptic number.

It is an amenable number.

1266621556 is a deficient number, since it is larger than the sum of its proper divisors (953746412).

1266621556 is a wasteful number, since it uses less digits than its factorization.

1266621556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540038 (or 540036 counting only the distinct ones).

The product of its digits is 129600, while the sum is 40.

The square root of 1266621556 is about 35589.6270843065. The cubic root of 1266621556 is about 1081.9710108936.

The spelling of 1266621556 in words is "one billion, two hundred sixty-six million, six hundred twenty-one thousand, five hundred fifty-six".