616521 has 4 divisors (see below), whose sum is σ = 822032. Its totient is φ = 411012.

The previous prime is 616519. The next prime is 616523. The reversal of 616521 is 125616.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (616519) and next prime (616523).

It is not a de Polignac number, because 616521 - 2¹ = 616519 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (616523) 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, 102751 + ... + 102756.

It is an arithmetic number, because the mean of its divisors is an integer number (205508).

2⁶¹⁶⁵²¹ is an apocalyptic number.

It is an amenable number.

616521 is a deficient number, since it is larger than the sum of its proper divisors (205511).

616521 is a wasteful number, since it uses less digits than its factorization.

616521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205510.

The product of its digits is 360, while the sum is 21.

The square root of 616521 is about 785.1885123969. The cubic root of 616521 is about 85.1103986505.

The spelling of 616521 in words is "six hundred sixteen thousand, five hundred twenty-one".