620661 has 4 divisors (see below), whose sum is σ = 827552. Its totient is φ = 413772.

The previous prime is 620657. The next prime is 620663. The reversal of 620661 is 166026.

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 not a de Polignac number, because 620661 - 2² = 620657 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (620663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103441 + ... + 103446.

It is an arithmetic number, because the mean of its divisors is an integer number (206888).

2⁶²⁰⁶⁶¹ is an apocalyptic number.

It is an amenable number.

620661 is a deficient number, since it is larger than the sum of its proper divisors (206891).

620661 is a wasteful number, since it uses less digits than its factorization.

620661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206890.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 620661 is about 787.8204110075. The cubic root of 620661 is about 85.3004820785.

Adding to 620661 its reverse (166026), we get a palindrome (786687).

The spelling of 620661 in words is "six hundred twenty thousand, six hundred sixty-one".