1555664561 has 8 divisors (see below), whose sum is σ = 1698490944. Its totient is φ = 1413071920.

The previous prime is 1555664527. The next prime is 1555664573. The reversal of 1555664561 is 1654665551.

It is a happy number.

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 1555664561 - 2⁶ = 1555664497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1555664581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44366 + ... + 71271.

It is an arithmetic number, because the mean of its divisors is an integer number (212311368).

Almost surely, 2^1555664561 is an apocalyptic number.

1555664561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1555664561 is a deficient number, since it is larger than the sum of its proper divisors (142826383).

1555664561 is a wasteful number, since it uses less digits than its factorization.

1555664561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116871.

The product of its digits is 540000, while the sum is 44.

The square root of 1555664561 is about 39441.9137593500. The cubic root of 1555664561 is about 1158.7026123654.

The spelling of 1555664561 in words is "one billion, five hundred fifty-five million, six hundred sixty-four thousand, five hundred sixty-one".