15664261 has 2 divisors, whose sum is σ = 15664262. Its totient is φ = 15664260.

The previous prime is 15664249. The next prime is 15664273. The reversal of 15664261 is 16246651.

It is a balanced prime because it is at equal distance from previous prime (15664249) and next prime (15664273).

It can be written as a sum of positive squares in only one way, i.e., 13432225 + 2232036 = 3665^2 + 1494^2 .

It is a cyclic number.

It is not a de Polignac number, because 15664261 - 2⁷ = 15664133 is a prime.

It is a super-2 number, since 2×15664261² = 490738145352242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15664211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7832130 + 7832131.

It is an arithmetic number, because the mean of its divisors is an integer number (7832131).

Almost surely, 2^15664261 is an apocalyptic number.

It is an amenable number.

15664261 is a deficient number, since it is larger than the sum of its proper divisors (1).

15664261 is an equidigital number, since it uses as much as digits as its factorization.

15664261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 31.

The square root of 15664261 is about 3957.8101268252. The cubic root of 15664261 is about 250.2092168644.

The spelling of 15664261 in words is "fifteen million, six hundred sixty-four thousand, two hundred sixty-one".