18313661 has 2 divisors, whose sum is σ = 18313662. Its totient is φ = 18313660.

The previous prime is 18313637. The next prime is 18313693. The reversal of 18313661 is 16631381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12996025 + 5317636 = 3605^2 + 2306^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18313661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18313601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9156830 + 9156831.

It is an arithmetic number, because the mean of its divisors is an integer number (9156831).

Almost surely, 2^18313661 is an apocalyptic number.

It is an amenable number.

18313661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18313661 is an equidigital number, since it uses as much as digits as its factorization.

18313661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 18313661 is about 4279.4463426943. The cubic root of 18313661 is about 263.5876492379.

It can be divided in two parts, 1831 and 3661, that multiplied together give a triangular number (6703291 = T₃₆₆₁).

The spelling of 18313661 in words is "eighteen million, three hundred thirteen thousand, six hundred sixty-one".