661519 has 4 divisors (see below), whose sum is σ = 684360. Its totient is φ = 638680.

The previous prime is 661517. The next prime is 661541. The reversal of 661519 is 915166.

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 661519 - 2¹ = 661517 is a prime.

It is a super-2 number, since 2×661519² = 875214774722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661513) 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, 11377 + ... + 11434.

It is an arithmetic number, because the mean of its divisors is an integer number (171090).

2⁶⁶¹⁵¹⁹ is an apocalyptic number.

661519 is a deficient number, since it is larger than the sum of its proper divisors (22841).

661519 is a wasteful number, since it uses less digits than its factorization.

661519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22840.

The product of its digits is 1620, while the sum is 28.

The square root of 661519 is about 813.3381830457. The cubic root of 661519 is about 87.1326202126.

The spelling of 661519 in words is "six hundred sixty-one thousand, five hundred nineteen".