670680821 has 8 divisors (see below), whose sum is σ = 712900440. Its totient is φ = 628768768.

The previous prime is 670680817. The next prime is 670680841. The reversal of 670680821 is 128086076.

It can be written as a sum of positive squares in 4 ways, for example, as 354907921 + 315772900 = 18839^2 + 17770^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 670680821 - 2² = 670680817 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (670680811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72386 + ... + 81123.

It is an arithmetic number, because the mean of its divisors is an integer number (89112555).

Almost surely, 2^670680821 is an apocalyptic number.

It is an amenable number.

670680821 is a deficient number, since it is larger than the sum of its proper divisors (42219619).

670680821 is a wasteful number, since it uses less digits than its factorization.

670680821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153783.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 670680821 is about 25897.5060768407. The cubic root of 670680821 is about 875.3303007696.

The spelling of 670680821 in words is "six hundred seventy million, six hundred eighty thousand, eight hundred twenty-one".