670521 has 4 divisors (see below), whose sum is σ = 894032. Its totient is φ = 447012.

The previous prime is 670517. The next prime is 670541. The reversal of 670521 is 125076.

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 670521 - 2² = 670517 is a prime.

It is a super-2 number, since 2×670521² = 899196822882, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

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

It is a Duffinian number.

670521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (670511) 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, 111751 + ... + 111756.

It is an arithmetic number, because the mean of its divisors is an integer number (223508).

2⁶⁷⁰⁵²¹ is an apocalyptic number.

It is an amenable number.

670521 is a deficient number, since it is larger than the sum of its proper divisors (223511).

670521 is a wasteful number, since it uses less digits than its factorization.

670521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223510.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 670521 is about 818.8534667448. The cubic root of 670521 is about 87.5260765817.

Adding to 670521 its reverse (125076), we get a palindrome (795597).

The spelling of 670521 in words is "six hundred seventy thousand, five hundred twenty-one".