670777621 has 2 divisors, whose sum is σ = 670777622. Its totient is φ = 670777620.

The previous prime is 670777573. The next prime is 670777649. The reversal of 670777621 is 126777076.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 579364900 + 91412721 = 24070^2 + 9561^2 .

It is a cyclic number.

It is not a de Polignac number, because 670777621 - 2¹⁵ = 670744853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (670777661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335388810 + 335388811.

It is an arithmetic number, because the mean of its divisors is an integer number (335388811).

Almost surely, 2^670777621 is an apocalyptic number.

It is an amenable number.

670777621 is a deficient number, since it is larger than the sum of its proper divisors (1).

670777621 is an equidigital number, since it uses as much as digits as its factorization.

670777621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172872, while the sum is 43.

The square root of 670777621 is about 25899.3749152369. The cubic root of 670777621 is about 875.3724111616.

The spelling of 670777621 in words is "six hundred seventy million, seven hundred seventy-seven thousand, six hundred twenty-one".