551423021 has 4 divisors (see below), whose sum is σ = 552392700. Its totient is φ = 550453344.

The previous prime is 551423011. The next prime is 551423051. The reversal of 551423021 is 120324155.

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

It can be written as a sum of positive squares in 2 ways, for example, as 194742025 + 356680996 = 13955^2 + 18886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551423021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551423011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 483986 + ... + 485123.

It is an arithmetic number, because the mean of its divisors is an integer number (138098175).

Almost surely, 2^551423021 is an apocalyptic number.

It is an amenable number.

551423021 is a deficient number, since it is larger than the sum of its proper divisors (969679).

551423021 is an equidigital number, since it uses as much as digits as its factorization.

551423021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 969678.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 551423021 is about 23482.3981100739. The cubic root of 551423021 is about 820.0272750198.

Adding to 551423021 its reverse (120324155), we get a palindrome (671747176).

The spelling of 551423021 in words is "five hundred fifty-one million, four hundred twenty-three thousand, twenty-one".