555720221661 has 16 divisors (see below), whose sum is σ = 850863498240. Its totient is φ = 319073811120.

The previous prime is 555720221621. The next prime is 555720221663. The reversal of 555720221661 is 166122027555.

It is not a de Polignac number, because 555720221661 - 2⁶ = 555720221597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (555720221663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 443157445 + ... + 443158698.

It is an arithmetic number, because the mean of its divisors is an integer number (53178968640).

Almost surely, 2^555720221661 is an apocalyptic number.

It is an amenable number.

555720221661 is a deficient number, since it is larger than the sum of its proper divisors (295143276579).

555720221661 is a wasteful number, since it uses less digits than its factorization.

555720221661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 886316176.

The product of its (nonzero) digits is 252000, while the sum is 42.

The spelling of 555720221661 in words is "five hundred fifty-five billion, seven hundred twenty million, two hundred twenty-one thousand, six hundred sixty-one".