507749821 has 4 divisors (see below), whose sum is σ = 514705372. Its totient is φ = 500794272.

The previous prime is 507749819. The next prime is 507749857. The reversal of 507749821 is 128947705.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128947705 = 5 ⋅25789541.

It can be written as a sum of positive squares in 2 ways, for example, as 159516900 + 348232921 = 12630^2 + 18661^2 .

It is a cyclic number.

It is not a de Polignac number, because 507749821 - 2¹ = 507749819 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 (507749861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3477666 + ... + 3477811.

It is an arithmetic number, because the mean of its divisors is an integer number (128676343).

Almost surely, 2^507749821 is an apocalyptic number.

It is an amenable number.

507749821 is a deficient number, since it is larger than the sum of its proper divisors (6955551).

507749821 is an equidigital number, since it uses as much as digits as its factorization.

507749821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6955550.

The product of its (nonzero) digits is 141120, while the sum is 43.

The square root of 507749821 is about 22533.3047065893. The cubic root of 507749821 is about 797.7802114746.

The spelling of 507749821 in words is "five hundred seven million, seven hundred forty-nine thousand, eight hundred twenty-one".