667621 has 4 divisors (see below), whose sum is σ = 696672. Its totient is φ = 638572.

The previous prime is 667577. The next prime is 667631. The reversal of 667621 is 126766.

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 667621 - 2¹¹ = 665573 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 667621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667631) 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, 14491 + ... + 14536.

It is an arithmetic number, because the mean of its divisors is an integer number (174168).

2⁶⁶⁷⁶²¹ is an apocalyptic number.

It is an amenable number.

667621 is a deficient number, since it is larger than the sum of its proper divisors (29051).

667621 is a wasteful number, since it uses less digits than its factorization.

667621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29050.

The product of its digits is 3024, while the sum is 28.

The square root of 667621 is about 817.0807793603. The cubic root of 667621 is about 87.3997109469.

The spelling of 667621 in words is "six hundred sixty-seven thousand, six hundred twenty-one".