505421551 has 4 divisors (see below), whose sum is σ = 521725504. Its totient is φ = 489117600.

The previous prime is 505421537. The next prime is 505421569. The reversal of 505421551 is 155124505.

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 505421551 - 2¹⁷ = 505290479 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 (505421351) 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, 8151930 + ... + 8151991.

It is an arithmetic number, because the mean of its divisors is an integer number (130431376).

Almost surely, 2^505421551 is an apocalyptic number.

505421551 is a deficient number, since it is larger than the sum of its proper divisors (16303953).

505421551 is a wasteful number, since it uses less digits than its factorization.

505421551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16303952.

The product of its (nonzero) digits is 5000, while the sum is 28.

The square root of 505421551 is about 22481.5824843359. The cubic root of 505421551 is about 796.5589446229.

The spelling of 505421551 in words is "five hundred five million, four hundred twenty-one thousand, five hundred fifty-one".