55505551661556 has 48 divisors (see below), whose sum is σ = 132626425244544. Its totient is φ = 18060613008256.

The previous prime is 55505551661507. The next prime is 55505551661591. The reversal of 55505551661556 is 65516615550555.

It is a happy number.

It is a super-2 number, since 2×55505551661556² (a number of 28 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 55505551661556.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221379480 + ... + 221630063.

It is an arithmetic number, because the mean of its divisors is an integer number (2763050525928).

Almost surely, 2^{55505551661556} is an apocalyptic number.

It is an amenable number.

55505551661556 is an abundant number, since it is smaller than the sum of its proper divisors (77120873582988).

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

55505551661556 is a wasteful number, since it uses less digits than its factorization.

55505551661556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443009800 (or 443009798 counting only the distinct ones).

The product of its (nonzero) digits is 84375000, while the sum is 60.

The spelling of 55505551661556 in words is "fifty-five trillion, five hundred five billion, five hundred fifty-one million, six hundred sixty-one thousand, five hundred fifty-six".