5661221555 has 12 divisors (see below), whose sum is σ = 7467198816. Its totient is φ = 4117251600.

The previous prime is 5661221537. The next prime is 5661221567. The reversal of 5661221555 is 5551221665.

It is not a de Polignac number, because 5661221555 - 2¹⁰ = 5661220531 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4678091 + ... + 4679300.

It is an arithmetic number, because the mean of its divisors is an integer number (622266568).

Almost surely, 2^5661221555 is an apocalyptic number.

5661221555 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

5661221555 is a deficient number, since it is larger than the sum of its proper divisors (1805977261).

5661221555 is a wasteful number, since it uses less digits than its factorization.

5661221555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9357418 (or 9357407 counting only the distinct ones).

The product of its digits is 90000, while the sum is 38.

The square root of 5661221555 is about 75241.0895388949. The cubic root of 5661221555 is about 1782.2558566733.

The spelling of 5661221555 in words is "five billion, six hundred sixty-one million, two hundred twenty-one thousand, five hundred fifty-five".