515551 has 4 divisors (see below), whose sum is σ = 519400. Its totient is φ = 511704.

The previous prime is 515539. The next prime is 515563. The reversal of 515551 is 155515.

515551 is nontrivially palindromic in base 2.

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

It is an interprime number because it is at equal distance from previous prime (515539) and next prime (515563).

It is a cyclic number.

It is not a de Polignac number, because 515551 - 2⁵ = 515519 is a prime.

It is a Duffinian number.

515551 is a lucky number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (515351) 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, 1716 + ... + 1993.

It is an arithmetic number, because the mean of its divisors is an integer number (129850).

2⁵¹⁵⁵⁵¹ is an apocalyptic number.

515551 is a deficient number, since it is larger than the sum of its proper divisors (3849).

515551 is a wasteful number, since it uses less digits than its factorization.

515551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3848.

The product of its digits is 625, while the sum is 22.

The square root of 515551 is about 718.0188019822. The cubic root of 515551 is about 80.1845219849.

The spelling of 515551 in words is "five hundred fifteen thousand, five hundred fifty-one".