617155661 has 2 divisors, whose sum is σ = 617155662. Its totient is φ = 617155660.

The previous prime is 617155639. The next prime is 617155667. The reversal of 617155661 is 166551716.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 609349225 + 7806436 = 24685^2 + 2794^2 .

It is a cyclic number.

It is not a de Polignac number, because 617155661 - 2¹⁴ = 617139277 is a prime.

It is a super-2 number, since 2×617155661² = 761762219808693842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (617155667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308577830 + 308577831.

It is an arithmetic number, because the mean of its divisors is an integer number (308577831).

Almost surely, 2^617155661 is an apocalyptic number.

It is an amenable number.

617155661 is a deficient number, since it is larger than the sum of its proper divisors (1).

617155661 is an equidigital number, since it uses as much as digits as its factorization.

617155661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 38.

The square root of 617155661 is about 24842.6178370960. The cubic root of 617155661 is about 851.3959350687.

It can be divided in two parts, 61715 and 5661, that added together give a palindrome (67376).

The spelling of 617155661 in words is "six hundred seventeen million, one hundred fifty-five thousand, six hundred sixty-one".