1266121555 has 8 divisors (see below), whose sum is σ = 1519958592. Its totient is φ = 1012488768.

The previous prime is 1266121523. The next prime is 1266121573. The reversal of 1266121555 is 5551216621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1266121555 - 2⁵ = 1266121523 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1266121555.

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, 37074 + ... + 62503.

It is an arithmetic number, because the mean of its divisors is an integer number (189994824).

Almost surely, 2^1266121555 is an apocalyptic number.

1266121555 is a deficient number, since it is larger than the sum of its proper divisors (253837037).

1266121555 is an equidigital number, since it uses as much as digits as its factorization.

1266121555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102125.

The product of its digits is 18000, while the sum is 34.

The square root of 1266121555 is about 35582.6018582115. The cubic root of 1266121555 is about 1081.8286221941.

The spelling of 1266121555 in words is "one billion, two hundred sixty-six million, one hundred twenty-one thousand, five hundred fifty-five".