16129661 has 2 divisors, whose sum is σ = 16129662. Its totient is φ = 16129660.

The previous prime is 16129657. The next prime is 16129679. The reversal of 16129661 is 16692161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8323225 + 7806436 = 2885^2 + 2794^2 .

It is a cyclic number.

It is not a de Polignac number, because 16129661 - 2² = 16129657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16129621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8064830 + 8064831.

It is an arithmetic number, because the mean of its divisors is an integer number (8064831).

Almost surely, 2^16129661 is an apocalyptic number.

It is an amenable number.

16129661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16129661 is an equidigital number, since it uses as much as digits as its factorization.

16129661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 32.

The square root of 16129661 is about 4016.1749214894. The cubic root of 16129661 is about 252.6630571149.

Subtracting 16129661 from its reverse (16692161), we obtain a square (562500 = 750²).

The spelling of 16129661 in words is "sixteen million, one hundred twenty-nine thousand, six hundred sixty-one".