620671661 has 2 divisors, whose sum is σ = 620671662. Its totient is φ = 620671660.

The previous prime is 620671657. The next prime is 620671697. The reversal of 620671661 is 166176026.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614742436 + 5929225 = 24794^2 + 2435^2 .

It is a cyclic number.

It is not a de Polignac number, because 620671661 - 2² = 620671657 is a prime.

It is a super-3 number, since 3×620671661³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620671621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310335830 + 310335831.

It is an arithmetic number, because the mean of its divisors is an integer number (310335831).

Almost surely, 2^620671661 is an apocalyptic number.

It is an amenable number.

620671661 is a deficient number, since it is larger than the sum of its proper divisors (1).

620671661 is an equidigital number, since it uses as much as digits as its factorization.

620671661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 620671661 is about 24913.2828226230. The cubic root of 620671661 is about 853.0097047356.

The spelling of 620671661 in words is "six hundred twenty million, six hundred seventy-one thousand, six hundred sixty-one".