556121791 has 4 divisors (see below), whose sum is σ = 557551800. Its totient is φ = 554691784.

The previous prime is 556121767. The next prime is 556121809. The reversal of 556121791 is 197121655.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 556121791 - 2¹⁹ = 555597503 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 556121791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (556121701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 714421 + ... + 715198.

It is an arithmetic number, because the mean of its divisors is an integer number (139387950).

Almost surely, 2^556121791 is an apocalyptic number.

556121791 is a deficient number, since it is larger than the sum of its proper divisors (1430009).

556121791 is a wasteful number, since it uses less digits than its factorization.

556121791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1430008.

The product of its digits is 18900, while the sum is 37.

The square root of 556121791 is about 23582.2346481414. The cubic root of 556121791 is about 822.3498879484.

The spelling of 556121791 in words is "five hundred fifty-six million, one hundred twenty-one thousand, seven hundred ninety-one".