551656020521 has 4 divisors (see below), whose sum is σ = 551657507472. Its totient is φ = 551654533572.

The previous prime is 551656020491. The next prime is 551656020541. The reversal of 551656020521 is 125020656155.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 551656020521 - 2⁶ = 551656020457 is a prime.

It is a super-2 number, since 2×551656020521² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551656020541) 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, 322010 + ... + 1098636.

It is an arithmetic number, because the mean of its divisors is an integer number (137914376868).

Almost surely, 2^551656020521 is an apocalyptic number.

It is an amenable number.

551656020521 is a deficient number, since it is larger than the sum of its proper divisors (1486951).

551656020521 is an equidigital number, since it uses as much as digits as its factorization.

551656020521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1486950.

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

Adding to 551656020521 its reverse (125020656155), we get a palindrome (676676676676).

The spelling of 551656020521 in words is "five hundred fifty-one billion, six hundred fifty-six million, twenty thousand, five hundred twenty-one".